34th International Symposium on Free Radicals

Hayama, Japan, 27 August ‒ 1 September 2017

http://kuchem.kyoto-u.ac.jp/bukka/radical/index.html

Table of Contents

Mission ································································································· 1

History ·································································································· 2

Topics & SupportList of Invited / Sponsors Speakers ··································································· 3

SupportGeneral Information/ Sponsors ··············································································· 4

GeneralList of Invited Information Speakers ··········································································· 75

Symposium ProgramProgram ·············································································· 98

Abstracts

Invited && HotHot TopicsTopics TalksTalks ·························································· 15 17

Special SessionSession onon NONO33 ······························································· 47 49

Poster Session AA ········································································ 55 57

Poster Session BB ········································································ 93 95

International AdvisoryAdvisory CommitteeCommittee ···························································· 130136

Local Organizers ···················································································· 131137

ParticipantsINDEX ···································································································’ Contact Information 132138

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Free radicals play a vital role as intermediates in many chemical reactions including those FreeFreeFreeFree involvedFreeradicals radicals radicals radicals radicals play inplay play combustionplay playa a vital a vital a vital avital rolevital role role role andasrole as asintermediates as intermediates chemical asintermediates intermediates intermediates synthesis, in in inmany inmany inmany many asmany chemical wellchemical chemical chemical chemical as ones reactions reactions reactions reactions inreactions the including includingatmosphere including including including those those those thoseand those in involvedinvolvedinvolvedinvolvedinterstellarinvolved in in incombustion incombustion incombustion combustion space.combustion The and and and Internationaland chemicaland chemical chemical chemical chemical synthesis, synthesis, synthesis,Free synthesis, synthesis, Radicals as as aswell aswell aswell Symposiumwell aswell as asones asones asones ones onesin in inthe wasinthe inthe theatmosphere theestablishedatmosphere atmosphere atmosphere atmosphere andnearly and and and inand in infifty in in interstellarinterstellarinterstellarinterstellaryearsinterstellar agospace. space. space. space. tospace. Thebring The The The International The International togetherInternational International International workers Free Free Free Free FreeRadicals Radicalsat Radicals Radicalsthe Radicals frontier Symposium Symposium Symposium Symposium Symposium of research was was was was establishedwas established inestablished established aestablished wide nearlyvariety nearly nearly nearly nearly fifty offifty fifty areasfifty fifty yearsyearsyearsyearsofyears ago ago freeago ago toago to toradical bring tobring tobring bring bring together chemistrytogether together together together workers workers workerswith workers workers particularat at atthe atthe atthe thefrontier thefrontier frontier emphasisfrontier frontier of of ofresearch ofresearch ofresearch onresearch research the in in spectroscopicina ina widein a wide a wide awide widevariety variety variety variety variety identification,of of ofareas ofareas ofareas areas areas ofof of freeoffree characterizationoffree free free radicalradical radical radical radical chemistrychemistry chemistry chemistry chemistry and withwith dynamicswith with with particularparticular particular particular particular of emphasisradicals.emphasis emphasis emphasis emphasis The on onon on theonthe compositionthe the spectroscopicthespectroscopic spectroscopic spectroscopic spectroscopic of identification,theidentification, identification, identification, identification,International characterizationcharacterizationcharacterizationcharacterizationCommitteecharacterization below, and and and and and dynamics guaranteesdynamics dynamics dynamicsdynamics of ofthe of ofradicals. ofradicals.high radicals. radicals.radicals. scientific The The The The The composition levelcomposition composition compositioncomposition of these of meetings.of of ofthe ofthe the the theInternational International International InternationalInternational CommitteeCommitteeCommitteeCommitteeCommittee below, below, below, below, below, guarantees guarantees guarantees guarantees guarantees the the the the high thehigh high high highscientific scientific scientific scientific scientific level level level level levelof of ofthese ofthese ofthese these these meetings. meetings. meetings. meetings. meetings. While the theme of present meetings remains the same as for the first Free Radicals WhileWhileWhileWhileWhileSymposium, the the the the theme thetheme theme theme theme theof of of experimentalpresent of present ofpresent present present meetings meetings meetings meetings andmeetings theoretical remain remain remain remain remains sthe s approaches,the sthe s the same thesame same same same as as as asfor as for as forwell for the forthe the as the first the first thefirst first firstFree applications,Free Free Free FreeRadicals Radicals Radicals Radicals Radicals have Symposium,Symposium,Symposium,Symposium,Symposium,advanced the the tremendously.the theexperimental theexperimental experimental experimental experimental Whereasand and and and theoreticaland theoretical theoretical theoretical attheoretical that approaches,time, approaches, approaches, approaches, approaches, the presence as as aswell aswell aswell well or aswell as asimportancethe asthe asthe theapplications, theapplications, applications, applications, applications, of free have have radicalshave have have advancedadvancedadvancedadvancedadvancedin a particular tremendously. tremendously. tremendously. tremendously. tremendously. process Whereas Whereas Whereas wasWhereas Whereas typically at at atthat atthat atthat that time,that onlytime, time, time, time, theinferred the the thepresence thepresence presence presence presenceor hypo or or orimportance orimportancethesized, orimportance importance importance today of of offree offree offreeusing free radicalsfree radicals radicals radicals modernradicals inin ina ina particularspectroscopicin a particular a particular aparticular particular process process process process meansprocess was was was ofwas typicallywas typicallydetection typically typically typically only only onlytheir only onlyinferred inferred inferredpresence inferred inferred or or or hypo orcannot hypo orhypo hypo hypothesized,thesized,thesized, onlythesized,thesized, be today today proventoday today today using using using butusing using modern themodern modern modern modernradicals spectroscopicspectroscopicspectroscopicspectroscopicspectroscopicthemselves means means characterizedmeans means means of of of detection ofdetection ofdetection detection detection in great their their their their detail. theirpresence presence presence presence presence Indeed cannot cannot cannot cannotwhat cannot only only onceonly only onlybe be bewas provenbe provenbe proven seenproven proven but butas but but "throughthe butthe the the radicals theradicals radicals radicals radicalsa glass themselvesthemselvesthemselvesthemselvesdarkly,"themselves characterized hascharacterized characterized characterized characterizednow been in in illuminatedingreat ingreat ingreat great great detail. detail. detail. detail. detail.brightly Indeed Indeed Indeed Indeed Indeed bywhat what whatlasers what what once once once andonce once was was wasother was seenwas seen seen seenmeans seenas as as "through as"through as "through of"through "through detection. a a glass a glass a glass aglass glass darkly,"darkly,"darkly,"darkly,"darkly," has has has has now hasnow now now nowbeen been been been been illuminated illuminated illuminated illuminated illuminated brightly brightly brightly brightly brightly by by by lasers by lasers bylasers lasers lasers and and and and otherand other other other other means means means means means of of ofdetection. ofdetection. ofdetection. detection. detection. The study of radicals, and their radiative and dynamical properties has shed light on a vast TheTheTheThe study Thevarietystudy study study study of of of ofradicals, ofradicals, ofradicals,physical radicals, radicals, and and andand and theirand their theirchemical their theirradiative radiative radiative radiative radiative processes. and and and and dynamicaland dynamical dynamical dynamical dynamicalThese properties processesproperties properties properties properties has spanhas has hasshed hasshed shedan shed shedlightenvironment light light light lighton on on aon aon vast avast avast avastfrom vast varietyvarietyvarietyvarietyvarietyinside of of of physical ofevery physical ofphysical physical physical living and and and and being,chemicaland chemical chemical chemical chemical through processes. processes. processes. processes. processes.the fires These These Theseof These Thesecombustion, processes processes processes processes processes span tospan span ourspan spanan an atmosphere,an environment an environment anenvironment environment environment and from from beyondfrom from from insideinsideinsideinsidetoinside every every theevery every every livingobservable living living living living being, being, being, being, being, limitsthrough through through through through of the theinterstellar the thefires thefires fires fires offires of ofcombustion, ofcombustion, space.ofcombustion, combustion, combustion, Indeed to to toour toour sometoour ouratmosphere, ouratmosphere, atmosphere, atmosphere, freeatmosphere, radicals and and and and beyondand beyondhave beyond beyond beyond been toto to theto thetoobserved the the observablethe observable observable observableobservable for the limits limits limitsfirst limitslimits of oftime of interstellar of interstellarof interstellarin interstellarinterstellar interstellar space. space. space. space.space. space Indeed Indeed Indeed Indeed Indeedbefore some some some sometheysome free free freecould free free radicals radicals radicals radicalsberadicals produced have have have have have been been been beeninbeen the observedobservedobservedobservedlaboratory.observed for for for for theforthe the Therefore the first thefirst first first firsttime time time time thetimein in in interstellar in Freeinterstellar ininterstellar interstellar interstellar Radicals space space space space Syspace before mposiabefore before before before they they arethey they theycould stronglycould could could could be be be producedbe interdisciplinaryproducedbe produced produced produced in in in the in the inthe the with the laboratory.laboratory.laboratory.laboratory.chemists,laboratory. Therefore Therefore Thereforephysicists, ThereforeTherefore the the astrophysicists the the Freethe Free Free Free Free Radicals Radicals Radicals RadicalsRadicals and Sy Symposia environmental mposiaSy SymposiamposiaSymposia are are are are stronglyare stronglyscientists strongly stronglystrongly interdisciplinary interdisciplinaryparticipating, interdisciplinary interdisciplinaryinterdisciplinary resulting with with with with with in chemists,chemists,chemists,chemists,achemists, conference physicists, physicists, physicists, physicists, physicists, unique astrophysicists astrophysicists astrophysicists astrophysicists astrophysicists in its creative and and and and environmental and environmentalinteraction environmental environmental environmental between scientists scientists scientists scientists scientists diverse participating, participating, participating, participating, participating,disciplines resulting resulting resulting inresulting resulting both in in theirin in in aa conference aconference aconference atheoreticalconference conference unique unique andunique unique unique experimental in in in its inits in its creative its creative itscreative creative creative aspects. interaction interaction interaction interaction interaction between between between between between diverse diverse diverse diverse diverse disciplines disciplines disciplines disciplines disciplines in in in both inboth inboth both boththeir their their their their theoreticaltheoreticaltheoreticaltheoreticaltheoretical and and and and experimentaland experimental experimental experimental experimental aspects. aspects. aspects. aspects. aspects.

1

111 11 History

Year Location Symposium Chair(s) 1956 Quebec City, QC, CANADA P. A. Giguere 1957 Washington DC, USA H. P. Broida, A. M. Bass 1958 Sheffield, UK G. Porter 1959 Washington DC, USA H. P. Broida, A. M. Bass 1961 Uppsala, SWEDEN S. Claesson 1963 Cambridge, UK B. A. Thrush 1965 Padua, ITALY G. Semerano 1967 Novosibirsk, USSR V. N. Kondratiev 1969 Banff, AB, CANADA H. Gunning, D. A. Ramsay 1971 Lyon, FRANCE M. Peyron 1973 Königssee, GERMANY W. Groth 1976 Laguna Beach, CA, USA E. K. C. Lee, F. S. Rowland 1977 Lyndhurst, Hants, UK A. Carrington 1979 Sanda, Hyogo-ken, JAPAN Y. Morino, I. Tanaka 1981 Ingonish, NS, CANADA W. E. Jones 1983 Lauzelles-Ottignies, BELGIUM R. Colin 1985 Granby, CO, USA K. M. Evenson, R. F. Curl, H. E. Radford 1987 Oxford, UK J. M. Brown 1989 Dalian, CHINA Postponed 1990 Susono, Shizuoka, JAPAN E. Hirota 1991 Williamstown, MA, USA S. D. Colson 1993 Doorworth, NETHERLANDS H. ter Meulen 1995 Victoria, BC, CANADA A. J. Merer 1997 Tallberg, SWEDEN M. Larsson 1999 Flagstaff, AZ, USA T. A. Miller 2001 Assisi, ITALY P. Casavecchia 2004 Taipei, TAIWAN Y. P. Lee 2005 Leysin, SWITZERLAND J. P. Maier, F. Merkt, M. Quack 2007 Big Sky, MT, USA R. E. Continetti 2009 Savonlinna, FINLAND L. Halonen, R. Timonen 2011 Port Douglas, AUSTRALIA E. J. Bieske, S. H. Kable 2013 Potsdam, GERMANY P. Botschwina, F. Temps 2015 Olympic Valley, CA, USA D. Chandler, C. Taatjes, D. Osborn

2 History Topics

Year Location Symposium Chair(s) Topics covered at the 34th International Symposium on Free Radicals (FRS2017) include: 1956 Quebec City, QC, CANADA P. A. Giguere • Spectroscopy of Free Radicals 1957 Washington DC, USA H. P. Broida, A. M. Bass • Structure of Free Radicals 1958 Sheffield, UK G. Porter • Chemical Kinetics and Dynamics of Radicals, Theory and Experiment 1959 Washington DC, USA H. P. Broida, A. M. Bass • Ultrafast Spectroscopy of Chemical Dynamics 1961 Uppsala, SWEDEN S. Claesson • Free Radicals as Reaction Intermediates 1963 Cambridge, UK B. A. Thrush • Free Radicals and Atmospheric Chemistry 1965 Padua, ITALY G. Semerano • Free Radicals and Combustion Chemistry Free Radicals and Interstellar 1967 Novosibirsk, USSR V. N. Kondratiev • • Cold Atoms and Molecules 1969 Banff, AB, CANADA H. Gunning, D. A. Ramsay

1971 Lyon, FRANCE M. Peyron

1973 Königssee, GERMANY W. Groth 1976 Laguna Beach, CA, USA E. K. C. Lee, F. S. Rowland Support / Sponsors 1977 Lyndhurst, Hants, UK A. Carrington The local organizers of the 34th International Symposium on Free Radicals gratefully 1979 Sanda, Hyogo-ken, JAPAN Y. Morino, I. Tanaka acknowledge the support of the following organizations and companies. 1981 Ingonish, NS, CANADA W. E. Jones

1983 Lauzelles-Ottignies, BELGIUM R. Colin 1985 Granby, CO, USA K. M. Evenson, R. F. Curl, H. E. The Morino Foundation for Molecular Science Radford http://regulus.mtrl1.info.hiroshima-cu.ac.jp/~morino-f/morino_web.html 1987 Oxford, UK J. M. Brown 1989 Dalian, CHINA Postponed The Kyoto University Foundation 1990 Susono, Shizuoka, JAPAN E. Hirota http://www.kyodai-zaidan.or.jp/ 1991 Williamstown, MA, USA S. D. Colson 1993 Doorworth, NETHERLANDS H. ter Meulen The Inoue Foundation for Science 1995 Victoria, BC, CANADA A. J. Merer http://www.inoue-zaidan.or.jp/ 1997 Tallberg, SWEDEN M. Larsson

1999 Flagstaff, AZ, USA T. A. Miller 2001 Assisi, ITALY P. Casavecchia PCCP (Royal Society of Chemistry) 2004 Taipei, TAIWAN Y. P. Lee http://www.rsc.org/journals-books-databases/about-journals/PCCP/ 2005 Leysin, SWITZERLAND J. P. Maier, F. Merkt, M. Quack 2007 Big Sky, MT, USA R. E. Continetti The Journal of Chemical Physics 2009 Savonlinna, FINLAND L. Halonen, R. Timonen http://aip.scitation.org/journal/jcp 2011 Port Douglas, AUSTRALIA E. J. Bieske, S. H. Kable 2013 Potsdam, GERMANY P. Botschwina, F. Temps 2015 Olympic Valley, CA, USA D. Chandler, C. Taatjes, D. Osborn

3 General Information

Lectures & Posters

All lectures (invited talks & hot topics) will be held at the Auditorium, which is the main conference hall of Shonan-Village Center. We request all the speakers to use their own laptop for their presentation, and test it prior to the respective session. The poster sessions will be held in the foyer in front of the Auditorium, both on the 28. August (Session A) and 29. August (Session B) from 8:30 PM to 10:30 PM. Prior to the poster sessions (at 7:30–8:30 PM), each poster presenter is also requested to give a 1-min. talk in the Auditorium to appeal their topic and highlight their main result.

45 General Information Accommodation We have arranged two facilities for accommodation, one directly at the venue (on-site, Lectures & Posters Shonan Village Center) and one at a nearby facility (off-site, Shonan OVA). The off-site All lectures (invited talks & hot topics) will be held at the Auditorium, which is the main facility is approximately 1 km or a 15-minute walk away from the venue. We provide the conference hall of Shonan-Village Center. We request all the speakers to use their own shuttle bus service between Shonan OVA and Shonan Village Center in the morning laptop for their presentation, and test it prior to the respective session. before the beginning of the first session and in the evening after the end of all official The poster sessions will be held in the foyer in front of the Auditorium, both on the 28. activities. August (Session A) and 29. August (Session B) from 8:30 PM to 10:30 PM. Prior to the poster sessions (at 7:30–8:30 PM), each poster presenter is also requested to give a 1-min. talk in the Auditorium to appeal their topic and highlight their main result.

5 56 Internet

Free Wi-Fi broadband internet access is available free of charge in the whole facility, both at Shonan Village Center and Shonan OVA.

Excursion & Banquet

In the afternoon on the 31. August, chartered busses will bring us to the tour destinations, the banquet and back to the venue. Our excursion will lead us to the nearby city Kamakura. Kamakura is an ancient city with rich history and a traditional atmosphere. In the evening we finish the day with a banquet at the Kamakura Park Hotel.More information about Kamakura can be found at: http://www.city.kamakura.kanagawa.jp/kamakura-kankou/en/

Local attraction

The venue at Shonan Village is situated close to major recreational areas with many tourist attractions. Do not hesitate to ask us about more details for the destination of your interest. We will also provide a more detailed guide of local attractions at the conference desk close to the Auditorium (see the map on page 4). More information about local attractions can be found at: http://kuchem.kyoto-u.ac.jp/bukka/radical/local_attractions.html

Important Telephone Numbers

International dialing code: +81 (Japan) FRS2017 Contact: +81-(0)80-1340-7832 (Stephan Thürmer) or +81-(0)90-9032-0190 (Takuya Horio) Shonan Village Center: +81-(0)46-855-1800 OVA: +81-(0)46-857-3001

***In case of emergency*** Contact the FRS2017 staff or reception desk of your accommodation immediately

Hospitals & Drug stores

There are no hospitals within walking distance of the venue. You can buy common medicine at the convenience store close to the venue (10 minutes walking distance). Please contact FRS2017 staffs or reception desk in your accommodation in case you feel sick during the Symposium.

6 Internet List of Invited Speakers Free Wi-Fi broadband internet access is available free of charge in the whole facility, both Sébastien Le Picard(Université de Rennes 1, France) at Shonan Village Center and Shonan OVA. Nami Sakai (RIKEN, Japan) Excursion & Banquet Sebastiaan van de Meerakker (Radbound University, Netherlands)

In the afternoon on the 31. August, chartered busses will bring us to the tour destinations, John Doyle (Harvard University, USA) the banquet and back to the venue. Our excursion will lead us to the nearby city Kamakura. Jos Oomens (Radbound University, Netherlands)

Kamakura is an ancient city with rich history and a traditional atmosphere. In the evening Stephan Schlemmer (Universität zu Köln, Germany) we finish the day with a banquet at the Kamakura Park Hotel.More information about Hyotcherl Ihee (Korea Advanced Institute of Science and Technology / Institute of Basic Kamakura can be found at: Science, South Korea) http://www.city.kamakura.kanagawa.jp/kamakura-kankou/en/ Arthur Suits (University of Missouri-Columbia, USA) Local attraction Marsha Lester (University of Pennsylvania, USA)

The venue at Shonan Village is situated close to major recreational areas with many tourist Yuan-Pern Lee (National Chiao Tung University / Institute of Atomic and Molecular attractions. Do not hesitate to ask us about more details for the destination of your Sciences, Academia Sinica, Taiwan) interest. We will also provide a more detailed guide of local attractions at the conference Asuka Fujii (Tohoku University, Japan) desk close to the Auditorium (see the map on page 4). More information about local Terry Miller (The Ohio State University, USA) attractions can be found at: Kopin Liu (Institute of Atomic and Molecular Sciences, Academia Sinica, Taiwan) http://kuchem.kyoto-u.ac.jp/bukka/radical/local_attractions.html Hua Guo (University of New Mexico, USA)

Important Telephone Numbers Xueming Yang (Dalian Institute of Chemical Physics / Chinese Academy of Sciences /

International dialing code: +81 (Japan) University of Science and Technology of China, China) FRS2017 Contact: +81-(0)80-1340-7832 (Stephan Thürmer) or Leonid Sheps (Sandia National Laboratories, USA) +81-(0)90-9032-0190 (Takuya Horio) Gabriel da Silva (The University of Melbourne, Australia)

Shonan Village Center: +81-(0)46-855-1800 Majed Chergui (École Polytechnique Fédérale de Lausanne, Switzerland) OVA: +81-(0)46-857-3001 Luis Bañares (Universidad Complutense de Madrid, Spain)

***In case of emergency*** Nadia Balucani (Università degli Studi di Perugia, Italy) Contact the FRS2017 staff or reception desk of your accommodation immediately Kenneth McKendrick (Heriot-Watt University, UK)

Hospitals & Drug stores

There are no hospitals within walking distance of the venue. You can buy common medicine at the convenience store close to the venue (10 minutes walking distance). Please contact FRS2017 staffs or reception desk in your accommodation in case you feel sick during the Symposium.

7

Symposium Program

98 Sunday, August 27, 2017

13:00 — 18:00 Registration

18:00 — 19:30 Welcome reception

Session 1: Astrophysics and Chemistry Chair: Kaori Kobayashi 19:30 — 20:10 S-01 Sébastien Le Picard (Université de Rennes 1) “Laboratory astrophysics: from fundamental gas phase reaction dynamics to molecular astrophysics”

20:10 — 20:50 S-02 Nami Sakai (RIKEN) “Tracing chemistry toward protoplanetary disks by ALMA”

20:50 — 21:10 H-01 Takeshi Oka (University of Chicago) + “Central 300 pc of the Galaxy probed by the IR spectrum of H3 ”

Monday, August 28, 2017

7:00 — 8:20 Breakfast

Session 2: Ultra Cold Collisions Chair: Hiroshi Kohguchi 8:20 — 8:30 Award Ceremony

8:30 — 9:10 S-03 Sebastiaan van de Meerakker (Radbound University) “Taming molecular collisions”

9:10 — 9:50 S-04 John Doyle (Harvard University) “Physics with cold and ultracold radicals”

9:50 — 10:10 H-02 Andreas Osterwalder (École Polytechnique Fédérale de Lausanne) “Merging, splitting, orienting – towards ultracold stereodynamics”

10:10 — 10:40 Coffee Break

Session 3: High-resolution spectroscopy Chair: Yasuki Endo 10:40 — 11:20 S-05 Jos Oomens (Radbound University) “Laboratory IR spectroscopy of gaseous, ionized polyaromatics of astrophysical interest”

10 11:20 — 12:00 S-06 Stephan Schlemmer (Universität zu Köln) “Radicals and ions in space and the laboratory”

12:00 — 12:20 H-03 Lauri Halonen (University of Helsinki) “Sub-Doppler molecular spectroscopy with a frequency comb referenced optical parametric oscillator”

12:20 — 13:30 Lunch

Special Session on NO3 Chair: Takeshi Oka 14:00 — 14:10 Introductory Remarks Takeshi Oka (University of Chicago)

14:10 — 14:30 N-01 Shunji Kasahara (Kobe University) “Rotationally-resolved high-resolution laser spectroscopy of B-X transition of nitrate radical”

14:30 — 14:50 N-02 Terry Miller (The Ohio State University)

“Cavity ringdown spectra of the a1’’ and e’ vibronic bands of the 2 2 Ã E’’- X̃ A’2 electronic transition of jet-cooled NO3”

14:50 — 15:10 N-03 Wolfgang Eisfeld (Bielefeld University)

“Quantum dynamics and potential energy surfaces of NO3”

15:10 — 15:30 Intermission

15:30 — 15:50 N-04 Koichi Yamada (National Institute of Advanced Industrial Science and Technology)

“Assignment of the PE spectrum of NO3 anion revisited”

15:50 — 16:10 N-05 Masaru Fukushima (Hiroshima City University)

“SVL DF and 2C-R4WM spectroscopies of NO3”

16:10 — 16:30 N-06 Eizi Hirota (SOKENDAI)

“Vibronic interactions in the NO3 ground electronic state”

16:30 — 16:40 Concluding Remarks Takeshi Oka (University of Chicago)

18:00 — 19:30 Dinner

19:30 — 22:30 1-min. Poster Talk & Poster Session A

11 Tuesday, August 29, 2017

7:00 — 8:20 Breakfast

Session 4: New Spectroscopic Methods Chair: David Osborn 8:30 — 9:10 S-07 Hyotcherl Ihee (Korea Advanced Institute of Science and Technology) “Visualizing reaction dynamics with femtosecond X-ray diffraction”

9:10 — 9:50 S-08 Arthur Suits (University of Missouri-Columbia) “New probes of reaction dynamics and spectroscopy in uniform supersonic flows”

9:50 — 10:10 H-04 Kenta Mizuse (Tokyo Institute of Technology) “Real-time imaging-based spectroscopy of nitrogen dimer”

10:10 — 10:40 Coffee Break

Session 5: Criegee Intermediates Chair: Scott Kable 10:40 — 11:20 S-09 Marsha Lester (University of Pennsylvania) “Unimolecular decay of Criegee intermediates to hydroxyl radical products”

11:20 — 12:00 S-10 Yuan-Pern Lee (National Chiao Tung University)

“Exploring reactions of Criegee intermediate CH2OO using a step-scan FTIR spectrometer”

12:00 — 12:20 H-05 Shinichi Enami (National Institute for Environmental Studies) “Reactions of Criegee intermediates at gas-aqueous interfaces”

12:20 — 13:30 Lunch

13:30 — 18:00 Free time

19:30 — 22:30 1-min. Poster Talk & Poster Session B

12 Wednesday, August 30, 2017

7:00 — 8:20 Breakfast

Session 6: Spectroscopy of Complex Systems Chair: Yasuhiro Ohshima 8:30 — 9:10 S-11 Asuka Fujii (Tohoku University) + + “Infrared spectroscopy of the (H2S)n and H (H2S)n clusters: What

is difference between H2S and H2O?”

9:10 — 9:50 S-12 Terry Miller (The Ohio State University) “The Jahn-Teller effect and degeneracy breaking in free radicals: Reconciling theory and experiment”

9:50 — 10:10 H-06 František Tureček (University of Washington) “Ground and excited states of biological radicals”

10:10 — 10:40 Coffee Break

Session 7: Reaction Dynamics I Chair: Kenji Honma 10:40 — 11:20 S-13 Kopin Liu (Institute of Atomic and Molecular Sciences) “Direct mapping of the key feature of the potential energy surface”

11:20 — 12:00 S-14 Hua Guo (University of New Mexico) “The strange world of nonadiabatic tunneling - The effect of geometric phase and diagonal Born-Oppenheimer correction”

12:00 — 12:20 H-07 Josep Anglada (Institut de Química Avançada de Catalunya)

“Atmospheric oxidation of NH3 by NO3 and OH radicals. Proton coupled electron transfer versus hydrogen atom transfer reaction mechanisms.”

12:20 — 13:30 Lunch

13:30 — 18:00 Free time

18:00 — 19:30 Dinner

13 Session 8: Kinetics and Dynamics Chair: Jim Lin 19:30 — 20:10 S-15 Xueming Yang (Dalian Institute of Chemical Physics) “Probing quantum dynamics of chemical reactions with high resolution H-atom Rydberg tagging and velocity map imaging”

20:10 — 20:50 S-16 Leonid Sheps (Sandia National Laboratories) “Direct time-resolved studies of radical intermediates in gas- phase oxidation reactions”

20:50 — 21:00 Short Break

21:00 — 21:40 S-17 Gabriel da Silva (The University of Melbourne) “Radical reaction mechanisms for organic nitrogen compounds in the atmosphere”

21:40 — 22:00 H-08 Christa Fittschen (Centre National de la Recherche Scientifique)

“HO2 yield in the reaction of different peroxy radicals with OH radicals”

14 Thursday, August 31, 2017

7:00 — 8:20 Breakfast

Session 9: Ultrafast Spectroscopy Chair: Mizuho Fushitani 8:30 — 9:10 S-18 Majed Chergui (École Polytechnique Fédérale de Lausanne) “Ultrafast chemical dynamics in solutions”

9:10 — 9:50 S-19 Luis Bañares (Universidad Complutense de Madrid) “Imaging the photodissociation of small hydrocarbon radicals”

9:50 — 10:10 H-09 Takuya Horio (Kyoto University) “Full observation of cascaded radiationless transitions from

S2(ππ*) state of pyrazine by ultrafast VUV photoelectron imaging”

10:10 — 10:40 Coffee Break

Session 10: Reaction Dynamics II Chair: Robert Continetti 10:40 — 11:20 S-20 Nadia Balucani (Università degli Studi di Perugia) “Reactions of atomic radicals with aliphatic and aromatic hydrocarbons by crossed beam experiments”

11:20 — 12:00 S-21 Kenneth McKendrick (Heriot-Watt University) “Real-space imaging of OH radicals scattered from liquid surfaces”

12:00 — 12:20 H-10 Yuxiang Mo (Tsinghua University) “Oscillation of branching ratios between the D(2s)+D(1s) and

the D(2p)+D(1s) channels in direct photodissociation of D2”

12:20 — 13:30 Lunch

13:30 — 18:00 Excursion

18:00 — 22:00 Banquet

Friday, September 1, 2017

7:00 — 9:00 Breakfast

9:00 — 12:00 Departure

15

Invited & Hot Topics Talks

(In Order of Presentation)

1715 S-01

Laboratory astrophysics: from fundamental gas phase reaction dynamics to molecular astrophysics

Sébastien D. Le Picard

Astrophysique de Laboratoire, Institut de Physique de Rennes, UMR 6251 Université de Rennes 1-CNRS 263 Avenue du Général Leclerc, 35 042 Rennes, France

Laboratory astrophysics aims to advance our understanding of the Universe through the promotion of experimental and theoretical research on the processes driving the Cosmos. Molecules are an important component of the universe which dominate the cooling of interstellar gas clouds and regulate star and planet formation as well as their atmospheres. The exploration of paths towards chemical complexity in these environments has direct bearing on the origin and evolution of life.

Many of the molecules detected in the interstellar medium, have been observed in the cold and dense core of the molecular clouds. The large range of species detected implies that a rich chemistry does take place despite the very low temperature (5 – 100 K) of these environments. However complex organic molecules (COMs) have long been detected in the interstellar medium, their formation routes remain uncertain. Both gas-phase and grain-surface reactions have been invoked to account for their presence. Pathways leading to the formation and growth of large molecules and aerosols in planetary atmospheres remain also far to be well understood.

Models of the composition of the interstellar medium and planetary atmospheres incorporate large networks of chemical reactions for which rate coefficients and product branching ratios are important components. The extreme conditions of temperature, the wide range of pressures and, in some cases, the non-local thermodynamic equilibrium regime encountered in astrophysical environments set a challenge to experimentalists and theoreticians who wish to measure and calculate data relevant for modelling interstellar clouds or planetary atmospheres. Some of them can be estimated with tolerable accuracy, others require high level electronic structure calculations coupled with detailed reaction dynamics investigation.

In this talk, I will present recent results and current experimental developments on low temperature (6 to 300 K) gas phase reaction kinetics and branching ratio determination of various collisional processes of interest for cold astrophysical environments. These results will illustrate the importance of combining theory and experiment.

18 S-02

Laboratory astrophysics: from fundamental gas phase reaction Tracing chemistry toward protoplanetary disks by ALMA dynamics to molecular astrophysics Nami Sakai Sébastien D. Le Picard RIKEN, 2-1, Hirosawa, Wako, Saitama, Japan Astrophysique de Laboratoire, Institut de Physique de Rennes, UMR 6251 Université de Rennes 1-CNRS 263 Avenue du Général Leclerc, 35 042 Rennes, France A new star is formed by gravitational contraction of an interstellar molecular cloud consisting of gas and dust. In the course of this process, a gas disk (protostellar/protoplanetary disk), whose size is an order of 100 AU, is formed around the protostar, and is evolved into a planetary system. The Solar system was also formed in this way about 4.6 billion years ago, and the life eventually emerged in the Earth. How is the situation happened for the Solar system unique in the Universe? In order to answer this question, understanding formation of protoplanetary disks and associated chemical evolution in Laboratory astrophysics aims to advance our understanding of the Universe through the promotion of various star-forming regions is essential, and various observational efforts have been done toward this experimental and theoretical research on the processes driving the Cosmos. Molecules are an goal. Increasing sensitivity of various telescopes allows us to identify 196 interstellar molecules so important component of the universe which dominate the cooling of interstellar gas clouds and far, about 1/3 of which are free radicals. They can survive for a long time in interstellar clouds, thanks regulate star and planet formation as well as their atmospheres. The exploration of paths towards to the extreme condition of low temperature (10-100 K) and low density (102-107 cm-3) in comparison chemical complexity in these environments has direct bearing on the origin and evolution of life. with the terrestrial condition. On the other hand, about 1/3 of the interstellar molecules are "complex" organic molecules having six or more atoms. This indicates the high chemical complexity of Many of the molecules detected in the interstellar medium, have been observed in the cold and dense interstellar clouds even in the extreme condition, which would ultimately be related to the origin of core of the molecular clouds. The large range of species detected implies that a rich chemistry does rich substances in the Solar System. take place despite the very low temperature (5 – 100 K) of these environments. However complex organic molecules (COMs) have long been detected in the interstellar medium, their formation routes In the last two decades, it is clearly demonstrated that envelopes as well as protostellar disks around remain uncertain. Both gas-phase and grain-surface reactions have been invoked to account for their solar-type protostars have significant chemical diversity: some sources harbor various saturated- presence. Pathways leading to the formation and growth of large molecules and aerosols in planetary "complex-" organic molecules (COMs) such as HCOOCH3, (CH3)2O, and C2H5CN [e.g. 1,2], whereas atmospheres remain also far to be well understood. some others harbor unsaturated species instead [e.g. 3,4]. The chemical diversity would originate from different duration time of the starless core phase of each protostar. In fact, sources showing Models of the composition of the interstellar medium and planetary atmospheres incorporate large intermediate-type of chemistry have also been found recently [e.g. 5]. On the other hand, the most networks of chemical reactions for which rate coefficients and product branching ratios are important interesting issue to be studied is how the chemical diversity in the protostellar envelopes/disks is components. The extreme conditions of temperature, the wide range of pressures and, in some cases, brought into the later stages toward protoplanetary disks. Fortunately, such studies are now feasible the non-local thermodynamic equilibrium regime encountered in astrophysical environments set a with high sensitivity and angular-resolution capabilities of ALMA (Atacama Large challenge to experimentalists and theoreticians who wish to measure and calculate data relevant for Millimeter/Submillimeter Array). Its early science operation was started from 2011 and spectacular modelling interstellar clouds or planetary atmospheres. Some of them can be estimated with tolerable images are being obtained after another. Some highlights and new questions coming from them will accuracy, others require high level electronic structure calculations coupled with detailed reaction be presented in relation to the chemical diversity. dynamics investigation.

In this talk, I will present recent results and current experimental developments on low temperature (6 to 300 K) gas phase reaction kinetics and branching ratio determination of various collisional processes of interest for cold astrophysical environments. These results will illustrate the importance of combining theory and experiment.

Figure: ALMA at 5000 m site in Chile

References [1] Cazaux, S., Tielens, A.G.G.M., Ceccarelli, C. et al. ApJL, 593, L51 (2003). [2] Oya, Y., Sakai, N., Lopez-Sepulcre, A. et al. ApJ, 824, 88 (2016). [3] Sakai, N. and Yamamoto, S. Chem. Rev. 113, 8981 (2013). [4] Sakai, N. Sakai, T., Hirota, T. et al. Natur., 507, 78 (2014). [5] Oya, Y., Sakai, N, Watanabe, Y. et al. ApJ, 837, 174 (2017).

1917 H-01

+ Central 300 pc of the Galaxy probed by the IR spectrum of H3 T. Okaa), T.R. Geballeb), M. Gotoc), T. Usudad), B.J. McCalle) and N. Indriolof)

a)Department of Astronomy and Astrophysics and Department of Chemistry, Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 USA b)Gemini Observatory, Hilo, HI 96720 USA c)Max Planck Institute of Extraterrestrial Physics, Garching, Germany d)National Astronomical Observatory of Japan, Tokyo, Japan e)Department of Chemistry and Department of Astronomy, University of Illinois at Urbana-Champaign,Urbana, IL 61801, USA f)Space Telescope Science Institute, Baltimore, MD 21218 USA

Our search for bright infrared stars with smooth continua suitable for 3.5-4.0-μm absorption + spectroscopy of H3 in the Galactic center (GC), initiated in 2008 [1], is nearing its completion. There are now nearly 50 stars that allow us to probe the 300-pc diameter Central Molecular Zone (CMZ) of + the GC through high sensitivity spectroscopy of H3 and CO. Our observations demonstrate that the -3 + + warm (T ~ 250 K) and diffuse (n < 100 cm ) gas with high column densities of H3 (N(H3 ) ~ 3×1015 cm-3) initially observed toward GCS3-2, the brightest infrared star in the CMZ [2], and later toward 8 stars in the central 30 pc [3] , covers more or less the entire CMZ.

-15 -1 The cosmic ray H2 ionization rate ζ ~ 3×10 s [2] we initially derived from these observations, which met skepticism as being too high, is now revised to be even 10 times higher influenced by the analysis of Le Petit et al. [4] using the Meudon PDR code. For such high ζ, our previous assumption that the electrons are only from the photoionization of C atoms is no longer valid, and electrons from cosmic ray ionization of H2 and H need to be taken into account. We have developed an approximate + model calculation considering only hydrogen and electrons. The relation between N(H3 ) and ζ is no longer as simple as the linear relation given earlier [2]. For each assumed cloud length L we obtain non-linear relation between ζ and the cloud density n. The separation of ζ and L cannot be uniquely done as in [2] but from various considerations we speculate that the following parameters best represent the warm diffuse gas: cloud length L ~ 100 pc, volume filling factor f ~ 2/3, ζ ~ 3×10-14 s-1, -3 + -5 -3 + -2 -3 n ~ 50 cm , n(H3 ) ~ 10 cm , n(H ) ~ ne ~ 5×10 cm .

Our work has radically changed the concept of the gas in the Galactic center: 1) The presence of dense gas (n ≥ 104 cm-3) with the originally proposed volume filling factor f ≥ 0.1, which would make the CMZ opaque at 3.5-4.0 μm is negated. Its value of f is < 10-2. 2) The newly found warm and diffuse gas dominates the region. The ultrahot (T ~ 108 K) X-ray emitting gas does not exist. The observed X-rays are from stars and their scattering by gas. 3) The ionization rate in the CMZ is ~ 1000 times higher than that in the solar vicinity. 4) The diffuse gas is radially expanding with the front velocity of ~ 140 km/s. 5) The top view of the CMZ is approximately circular with a radius r ~ 150 pc and the currently popular elliptic structure with high eccentricity is negated.

This work concludes the first author’s triple jump: the hop from 1975-80, the laboratory detection of + + the H3 spectrum [5]; the step 1981-1996, the detection of interstellar H3 with Tom Geballe [6]; and + the longest jump 1997-2017, the study of the GC using H3 .

References [1] Geballe, T.R., & Oka, T. ApJL, 709, L70 (2010). [2] Oka, T., Geballe, T.R., Goto, M., Usuda, T., & McCall, B.J. ApJ, 632:882 (2005) [3] Goto, M., Usuda, Nagata, Geballe, McCall, Indriolo, Suto, Henning, Morong, & Oka ApJ, 688:306 (2008) [4] Le Petit, F., Ruaud, M., Bron, E., Godard, B., Roueff, Languignon, & Le Bourlot A&A, 585, A105 (2016) [5] Oka, T. Phys. Rev. Lett. 45. 531 (1980) [6] Geballe, T.R. & Oka, T. Nature, 384,334 (1996)

2018 S-03

+ Central 300 pc of the Galaxy probed by the IR spectrum of H3 Taming Molecular Collisions

T. Okaa), T.R. Geballeb), M. Gotoc), T. Usudad), B.J. McCalle) and N. Indriolof) Sebastiaan Y.T. van de Meerakker a)Department of Astronomy and Astrophysics and Department of Chemistry, Radboud University, Institute for Molecules and Materials, Nijmegen, the Netherlands Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 USA b)Gemini Observatory, Hilo, HI 96720 USA c)Max Planck Institute of Extraterrestrial Physics, Garching, Germany The study of molecular collisions with the highest possible detail has been an important research d)National Astronomical Observatory of Japan, Tokyo, Japan theme in physical chemistry for decades. Over the last years we have developed methods to get e)Department of Chemistry and Department of Astronomy, improved control over molecules in a molecular beam. With the Stark decelerator, a part of a University of Illinois at Urbana-Champaign,Urbana, IL 61801, USA molecular beam can be selected to produce bunches of molecules with a computer-controlled velocity f)Space Telescope Science Institute, Baltimore, MD 21218 USA and with longitudinal temperatures as low as a few mK. The molecular packets that emerge from the decelerator have small spatial and angular spreads, and have almost perfect quantum state purity. Our search for bright infrared stars with smooth continua suitable for 3.5-4.0-μm absorption These tamed molecular beams are excellent starting points for high-resolution crossed beam scattering + spectroscopy of H3 in the Galactic center (GC), initiated in 2008 [1], is nearing its completion. There experiments. are now nearly 50 stars that allow us to probe the 300-pc diameter Central Molecular Zone (CMZ) of + the GC through high sensitivity spectroscopy of H3 and CO. Our observations demonstrate that the I will discuss our most recent results on the combination of Stark deceleration and velocity map -3 + + warm (T ~ 250 K) and diffuse (n < 100 cm ) gas with high column densities of H3 (N(H3 ) ~ imaging. The narrow velocity spread of Stark-decelerated beams results in scattering images with an 3×1015 cm-3) initially observed toward GCS3-2, the brightest infrared star in the CMZ [2], and later unprecedented sharpness and angular resolution. This has facilitated the observation of diffraction toward 8 stars in the central 30 pc [3] , covers more or less the entire CMZ. oscillations in the state-to-state differential cross sections for collisions of NO with rare gas atoms, the observation of scattering resonances at low-energy inelastic NO-He and NO-H2 collisions that -15 -1 The cosmic ray H2 ionization rate ζ ~ 3×10 s [2] we initially derived from these observations, reveal the influence of individual partial waves to the scattering dynamics, and product-pair which met skepticism as being too high, is now revised to be even 10 times higher influenced by the correlations for bimolecular scattering processes. analysis of Le Petit et al. [4] using the Meudon PDR code. For such high ζ, our previous assumption that the electrons are only from the photoionization of C atoms is no longer valid, and electrons from cosmic ray ionization of H2 and H need to be taken into account. We have developed an approximate + model calculation considering only hydrogen and electrons. The relation between N(H3 ) and ζ is no longer as simple as the linear relation given earlier [2]. For each assumed cloud length L we obtain non-linear relation between ζ and the cloud density n. The separation of ζ and L cannot be uniquely done as in [2] but from various considerations we speculate that the following parameters best represent the warm diffuse gas: cloud length L ~ 100 pc, volume filling factor f ~ 2/3, ζ ~ 3×10-14 s-1, -3 + -5 -3 + -2 -3 n ~ 50 cm , n(H3 ) ~ 10 cm , n(H ) ~ ne ~ 5×10 cm .

Our work has radically changed the concept of the gas in the Galactic center: 1) The presence of dense gas (n ≥ 104 cm-3) with the originally proposed volume filling factor f ≥ 0.1, which would make the CMZ opaque at 3.5-4.0 μm is negated. Its value of f is < 10-2. 2) The newly found warm and diffuse gas dominates the region. The ultrahot (T ~ 108 K) X-ray emitting gas does not exist. The observed X-rays are from stars and their scattering by gas. 3) The ionization rate in the CMZ is ~ 1000 times higher than that in the solar vicinity. 4) The diffuse gas is radially expanding with the front velocity of ~ 140 km/s. 5) The top view of the CMZ is approximately circular with a radius r ~ 150 pc and the currently popular elliptic structure with high eccentricity is negated.

This work concludes the first author’s triple jump: the hop from 1975-80, the laboratory detection of + + the H3 spectrum [5]; the step 1981-1996, the detection of interstellar H3 with Tom Geballe [6]; and + the longest jump 1997-2017, the study of the GC using H3 .

References [1] Geballe, T.R., & Oka, T. ApJL, 709, L70 (2010). [2] Oka, T., Geballe, T.R., Goto, M., Usuda, T., & McCall, B.J. ApJ, 632:882 (2005) [3] Goto, M., Usuda, Nagata, Geballe, McCall, Indriolo, Suto, Henning, Morong, & Oka ApJ, 688:306 (2008) [4] Le Petit, F., Ruaud, M., Bron, E., Godard, B., Roueff, Languignon, & Le Bourlot A&A, 585, A105 (2016) [5] Oka, T. Phys. Rev. Lett. 45. 531 (1980) [6] Geballe, T.R. & Oka, T. Nature, 384,334 (1996)

18 2119 S-04

Physics with Cold and Ultracold Radicals

John M. Doyle

Harvard University Department of Physics, 17 Oxford Street, Cambridge, MA USA

Cold and ultracold radical molecules are emerging as a quantum object of choice for many of the forefront physics research areas where atomic resonance methods are used. They are already used in searches for new physics beyond the Standard Model at the >10 TeV scale. Their use in condensed matter quantum simulation is well described theoretically, but the paucity of sources of ultracold molecules has held back progress. . I will give a brief overview of a method now routinely used to bring radical molecules into the cold (~1 K) regime, either in a cell or beam – buffer-gas cooling. I will describe experiments in laser cooling of buffer gas cooled diatomic and polyatomic molecules and our success in cooling into the sub-millikelvin regime. The latest results portend new experimental research avenues, including in the area of quantum simulation of spin-lattice systems.

2220 H-02

Physics with Cold and Ultracold Radicals Merging, splitting, orienting – towards ultracold stereodynamics John M. Doyle Sean Gordon, Junwen Zhou, Silvia Tanteri, and Andreas Osterwalder Harvard University Department of Physics, 17 Oxford Street, Cambridge, MA USA Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Cold and ultracold radical molecules are emerging as a quantum object of choice for many of the Switzerland [email protected] forefront physics research areas where atomic resonance methods are used. They are already used in searches for new physics beyond the Standard Model at the >10 TeV scale. Their use in condensed Merged neutral beams have enabled the investigation of sub-Kelvin chemical reactions in molecular matter quantum simulation is well described theoretically, but the paucity of sources of ultracold beams. In the past years we have conducted several Penning ionization studies of polyatomic molecules has held back progress. . I will give a brief overview of a method now routinely used to molecules, targeting characteristics arising from the presence of multiple rotational degrees of bring radical molecules into the cold (~1 K) regime, either in a cell or beam – buffer-gas cooling. I freedom and from the anisotropic shape of such systems are accessible. Here I will give an overview will describe experiments in laser cooling of buffer gas cooled diatomic and polyatomic molecules of our recent experiments on stereo dynamical aspects where we orient, e.g., the angular momentum and our success in cooling into the sub-millikelvin regime. The latest results portend new of a metastable rare gas atom prior to reaction. Strong orientation-dependent changes in the branching experimental research avenues, including in the area of quantum simulation of spin-lattice systems. ratio between different reaction channels permit the determination of state-specific reaction cross sections for levels that differ only by their magnetic quantum number.

Figure 1: 3D printed, electroplated beam splitter for polar neutral molecules.

I will also present a new method to produce electrically conductive structures for, e.g., high-voltage applications inside high-vacuum: the 3D printing of a plastic structure, followed by electroplating. This approach opens many possibilities for the generation of scientific apparatus, and it will greatly simplify and accelerate the design, production, testing, and exchange of experimental components. We have recently used this method for the first time by printing the beam splitter for neutral polar molecules shown in figure 1.[1] With this device a single supersonic expansion is split, using electrostatic guides, into two nearly identical components. This permits, for example, differential measurements with correlated probe and reference beams.

References [1] S. D. S. Gordon and A. Osterwalder, Phys.Rev.Applied 7, 044022(2017)

20 2321 S-05

Laboratory IR spectroscopy of gaseous, ionized polyaromatics of astrophysical interest

Jos Oomensa), Giel Berdena) and Jordy Bouwmanb)

a)FELIX Laboratory, Radboud University, Toernooiveld 7c, Nijmegen, The Netherlands b)Now at: Leiden Observatory, University of Leiden, The Netherlands

Large carbonaceous molecules including in particular polycyclic aromatic hydrocarbons (PAHs) have been hypothesized to occur abundantly in the interstellar medium (ISM). Some reckon that up to 20% of the interstellar carbon budget may be locked up in these physically and chemically stable compounds. Evidence for their abundant presence is based mainly on the observation of a series of IR emission bands which show the spectroscopic fingerprint of ‘generic’ PAH species. It is also evident that ionized PAHs are prevalent especially in photon dominated regions of the ISM.

Our lab has focused on laboratory investigations of the IR spectroscopy and breakdown chemistry of gaseous, ionized PAHs using the combination of an IR free electron laser and tandem mass spectrometry.[1] These studies serve on the one hand to evaluate the gas-phase IR spectra of ionized species and to benchmark computed IR spectra, and on the other hand to investigate the products that are formed in the energetic processing of these species as may occur under interstellar conditions.

I will show various recent examples of positively and negatively charged PAHs, having either a closed or open-shell electronic structure. For instance, we investigated the products formed in the energetic [2] + processing of the naphthalene cation, especially the product formed upon acetylene loss, C10H8 → + + C8H6 + C2H2. Various isomers, some of which nearly iso-energetic, are conceivable for the C8H6 product ion; the IR spectrum recorded for this mass isolated product ion reveals its structure to be that of pentalene, consisting of two fused 5-membered rings. This and other studies suggest a facile conversion of aromatic 6-membered ring species to 5-membered ring species, which could be an indication for a facile conversion of PAHs to fullerenes in interstellar environments.

References [1] J. Oomens, A.G.G.M. Tielens, B.G. Sartakov, G. von Helden, G. Meijer, Astrophys. J. 591, 968 (2003) [2] J. Bouwman, A.J. de Haas, J. Oomens, Chem. Commun. 52, 2636 (2016)

2422 S-06

Laboratory IR spectroscopy of gaseous, ionized polyaromatics Radicals and Ions in Space and the Laboratory of astrophysical interest a) a) a) a) Stephan Schlemmer , Sven Fanghänel , Oskar Asvany , Pavol Jusko , Sandra Jos Oomensa), Giel Berdena) and Jordy Bouwmanb) Brünkena) and Hiroshi Kohguchib), a)FELIX Laboratory, Radboud University, Toernooiveld 7c, Nijmegen, The Netherlands a) I. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany b)Now at: Leiden Observatory, University of Leiden, The Netherlands b) Department of Chemistry, School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526, Japan Large carbonaceous molecules including in particular polycyclic aromatic hydrocarbons (PAHs) have been hypothesized to occur abundantly in the interstellar medium (ISM). Some reckon that up to 20% Radicals and ions play an important role in the chemistry of the interstellar medium, the region in of the interstellar carbon budget may be locked up in these physically and chemically stable space in between the stars. Often energy barriers along the reaction paths are missing for this class of compounds. Evidence for their abundant presence is based mainly on the observation of a series of atoms and molecules such that reaction rates can be larger by orders of magnitude compared to IR emission bands which show the spectroscopic fingerprint of ‘generic’ PAH species. It is also reactions with closed shell species. As a consequence they are pivotal for the chemical evolution of evident that ionized PAHs are prevalent especially in photon dominated regions of the ISM. our universe. For this reason it is important to obtain a full account of the chemical inventory in space based on molecular spectroscopy of radicals and ions in the laboratory. Equally important are the Our lab has focused on laboratory investigations of the IR spectroscopy and breakdown chemistry of measurements of rate coefficients for reactive and inelastic processes in order to predict abundances gaseous, ionized PAHs using the combination of an IR free electron laser and tandem mass and to compare those with astrophysical observations. New telescopes like the Atacama Large spectrometry.[1] These studies serve on the one hand to evaluate the gas-phase IR spectra of ionized Millimeter Array (ALMA) allow detecting many such trace species with unprecedented sensitivity as species and to benchmark computed IR spectra, and on the other hand to investigate the products that well as angular resolution and as such challenge our understanding of the life cycle of stars and planets are formed in the energetic processing of these species as may occur under interstellar conditions. [1].

Based on the method of light induced reactions (LIR), established in our laboratory over the last 10 - I will show various recent examples of positively and negatively charged PAHs, having either a closed 20 years, spectra of many important molecular ions could be obtained for the first time. Examples or open-shell electronic structure. For instance, we investigated the products formed in the energetic + + + + + + + + [2] + include spectra of N2 , C2H2 , H2D , D2H , CH2D , CD2H , H3 and also CH5 [2] taken mainly in the processing of the naphthalene cation, especially the product formed upon acetylene loss, C10H8 → + + mid-IR regime. Some of these spectra are taken at very high resolution. Calibration to the teeth of a C8H6 + C2H2. Various isomers, some of which nearly iso-energetic, are conceivable for the C8H6 frequency comb allows the determination of the ro-vibrational lines to sub - MHz accuracy, [3]. product ion; the IR spectrum recorded for this mass isolated product ion reveals its structure to be that Subsequently pure rotational transitions are predicted from these lines for an unambiguous of pentalene, consisting of two fused 5-membered rings. This and other studies suggest a facile identification in the astrophysical spectra. Moreover, for many molecules rotational transitions are conversion of aromatic 6-membered ring species to 5-membered ring species, which could be an determined to kHz accuracy based on FIR-IR double resonance absorption or by the determination of indication for a facile conversion of PAHs to fullerenes in interstellar environments. state dependent attachment rates of the molecule with He atoms. Examples along these lines include + + + + + - the species mentioned above but also CD , C3H , NH3D , C2H , O2H , or even diatomics like OH [4], SiH+, or CH+. Recent examples of these molecular spectra will be discussed.

One of the most basic reactions concerns the first step in the formation of interstellar ammonia, NH3, + + namely the reactive collision N + H2 → NH + H. At collision temperatures around 10 K, like those in molecular clouds, the outcome of the reaction, which is nearly thermoneutral, is strongly state dependent, i.e. slow for the energetic o-H2 (J = 1, Erot/k = 170 K) but even much slower, if not vanishing, for p-H2. (J = 0, Erot/k = 0 K). As a consequence interstellar formation of ammonia strongly depends on the ortho to para ratio of H2 in these astrophysical environments. In recent years we try to investigate the influence of the fine structure state, J = 0 or 1 or 2, of the N+ atom in this collision process, which could not be addressed in detail experimentally before. These experiments are much more demanding than those for spectroscopy in ion traps. Preliminary results on fine structure inelastic N+ + He collisions will be discussed in this contribution.

References [1] S. Brünken, O. Sipilä, E.T. Chambers, J. Harju, P. Caselli, O. Asvany, C.E. Honingh, T. Kamiński, K.M. Menten, J. Stutzki, and S. Schlemmer, An age of at least 1 Myr for a dense cloud core forming Sun-like stars. Nature, 516, 219–221 (2014) DOI:10.1038/nature13924 [2] O. Asvany, K.M.T. Yamada, S. Brünken, A. Potapov, S. Schlemmer, Experimental Ground State + Combination Differences of CH5 , Science 347 (2015) 1346-1349, DOI: 10.1126/science.aaa3304. References [3] O. Asvany, J. Krieg, and S. Schlemmer, Frequency comb assisted mid-infrared spectroscopy of cold [1] J. Oomens, A.G.G.M. Tielens, B.G. Sartakov, G. von Helden, G. Meijer, Astrophys. J. 591, 968 (2003) molecular ions, Review of Scientific Instruments, 83 (2012), 076102. [2] J. Bouwman, A.J. de Haas, J. Oomens, Chem. Commun. 52, 2636 (2016) [4] P. Jusko, O. Asvany, A.-C. Wallerstein, S. Brünken, S. Schlemmer, Two photon rotational action spectroscopy of cold OH- at 1 ppb accuracy, Phys.Rev.Lett. 112 (2014) 253005.

22 2523 H-03

Sub-Doppler molecular spectroscopy with a frequency comb referenced optical parametric oscillator

Lauri Halonen, Juho Karhu, Markku Vainio, and Markus Metsälä

Department of Chemistry, University of Helsinki, Helsinki, Finland

Optical frequency combs (OFC) can be used as accurate optical frequency references, which makes them valuable tools in spectroscopy and kinetics, when applied to various molecular species including free radicals. A laser source locked to an OFC reference has a stable and accurately known wavelength, which is advantageous in applications that require high resolution, such as sub-Doppler spectroscopy. For spectroscopy, an important prospect is the expansion of the OFC technologies into the mid- infrared wavelength region, where the strong fundamental vibrational transitions are found [1]. We have produced a fully-stabilized mid-infrared OFC using a synchronously pumped degenerate femtosecond optical parametric oscillator (fs-OPO) [2]. This comb serves as a direct frequency reference for the stabilization of the idler wavelength of a continuous-wave optical parametric oscillator (CW-OPO), which was used as a light source in molecular laser spectroscopy. We have utilized the OFC stabilized CW-OPO in two sub-Doppler spectroscopy experiments with the resolution and accuracy below 1 MHz. First, we performed saturation spectroscopy of methane in a Lamb-dip configuration. The frequency stabilized CW-OPO idler beam was reflected back and forth through a 50 cm cuvette containing 30 mTorr of methane. The idler wavelength was modulated through the pump beam. The first derivative signal of the Lamb-dip was recorded with a lock-in amplifier (Fig. 1). The idler wavelength was scanned by tuning the OFC reference. The stabilized CW-OPO was also used in a two-photon vibrational spectroscopy setup [3]. The CW-OPO pumps a strong mid-infrared transition of acetylene, and a second transition, from the pumped state to an infrared-inactive vibrational state, is recorded with an external-cavity diode laser (ECDL). The ECDL is itself stabilized to the near-infrared OFC that also pumps the fs-OPO. With a free-running CW- OPO, the time available for the measurement of the spectrum is limited to a few seconds, since the CW-OPO long-term frequency drifts are larger than the linewidth of the two-photon transition. With the stabilized CW-OPO and ECDL, we could resolve the shape of the narrow, sub-Doppler transition line with high resolution and a high signal-to-noise ratio (Fig. 1).

Fig. On left: Lamb-dip spectrum of the methane symmetric CH-stretching vibration. Black dots are the measured points and the solid line is their low-pass filtered average. The zero of the frequency axis corresponds to the line center frequency 92 232 636.917 MHz. On right: Two-photon absorption spectrum of acetylene transition R(17) of the band ν1 + 2ν3 ← ν3. The spectrum is measured with cavity ring-down spectroscopy when the stabilized CW-OPO idler beam pumps the J=17 rovibrational state of ν3.

References [1] M. Vainio and L. Halonen, Physical Chemistry Chemical Physics 18, 4266 (2016). [2] M. Vainio and J. Karhu, Optics Express 25, 4190 (2017). [3] J. Karhu, M. Vainio, M. Metsälä, and L. Halonen, Optics Express 25, 4688 (2017).

2624 S-07

Sub-Doppler molecular spectroscopy with a frequency comb Visualizing reaction dynamics with femtosecond X-ray referenced optical parametric oscillator diffraction

Lauri Halonen, Juho Karhu, Markku Vainio, and Markus Metsälä Hyotcherl Iheea)b)

Department of Chemistry, University of Helsinki, Helsinki, Finland a)Department of Chemistry, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, South Korea b)Center for Nanomaterials and Chemical Reactions, IBS, 291 Daehak-ro, Yuseong-gu, Daejeon, South Korea Optical frequency combs (OFC) can be used as accurate optical frequency references, which makes them valuable tools in spectroscopy and kinetics, when applied to various molecular species including The pump-probe X-ray diffraction and scattering techniques have now been fully established as a free radicals. A laser source locked to an OFC reference has a stable and accurately known wavelength, powerful method to investigate molecular structural dynamics [1-5]. We have employed the which is advantageous in applications that require high resolution, such as sub-Doppler spectroscopy. techniques to study structural dynamics and spatiotemporal kinetics of many molecular systems For spectroscopy, an important prospect is the expansion of the OFC technologies into the mid- including diatomic molecules, haloalkanes, organometallic complexes and protein molecules over infrared wavelength region, where the strong fundamental vibrational transitions are found [1]. We timescales from ps to milliseconds. X-ray crystallography, the major structural tool to determine 3D have produced a fully-stabilized mid-infrared OFC using a synchronously pumped degenerate structures of proteins, can be extended to time-resolved X-ray crystallography with a laser-excitation femtosecond optical parametric oscillator (fs-OPO) [2]. This comb serves as a direct frequency and X-ray-probe scheme, but has been limited to a few model systems due to the stringent reference for the stabilization of the idler wavelength of a continuous-wave optical parametric prerequisites such as highly-ordered and radiation-resistant single crystals. These problems can be oscillator (CW-OPO), which was used as a light source in molecular laser spectroscopy. We have overcome by applying time-resolved X-ray diffraction directly to protein solutions rather than protein utilized the OFC stabilized CW-OPO in two sub-Doppler spectroscopy experiments with the single crystals. To emphasize that structural information can be obtained from the liquid phase, this resolution and accuracy below 1 MHz. First, we performed saturation spectroscopy of methane in a time-resolved X-ray solution scattering technique is named time-resolved X-ray liquidography Lamb-dip configuration. The frequency stabilized CW-OPO idler beam was reflected back and forth (TRXL) in analogy to time-resolved X-ray crystallography where the structural information of through a 50 cm cuvette containing 30 mTorr of methane. The idler wavelength was modulated reaction intermediates is obtained from the crystalline phase. We will present our recent results through the pump beam. The first derivative signal of the Lamb-dip was recorded with a lock-in including the achievement of femtosecond TRXL by using an X-ray free electron laser. amplifier (Fig. 1). The idler wavelength was scanned by tuning the OFC reference. The stabilized CW-OPO was also used in a two-photon vibrational spectroscopy setup [3]. The CW-OPO pumps a strong mid-infrared transition of acetylene, and a second transition, from the pumped state to an infrared-inactive vibrational state, is recorded with an external-cavity diode laser (ECDL). The ECDL is itself stabilized to the near-infrared OFC that also pumps the fs-OPO. With a free-running CW- OPO, the time available for the measurement of the spectrum is limited to a few seconds, since the CW-OPO long-term frequency drifts are larger than the linewidth of the two-photon transition. With the stabilized CW-OPO and ECDL, we could resolve the shape of the narrow, sub-Doppler transition line with high resolution and a high signal-to-noise ratio (Fig. 1).

References Fig. On left: Lamb-dip spectrum of the methane symmetric CH-stretching vibration. Black dots are the measured points and the solid line is their low-pass filtered average. The zero of the frequency axis corresponds to the line [1] K. H. Kim, J. G. Kim, S. Nozawa, T. Sato, K. Y. Oang, T. W. Kim, H. Ki, J. Jo, S. Park, C. Song, T. Sato, center frequency 92 232 636.917 MHz. On right: Two-photon absorption spectrum of acetylene transition R(17) K. Ogawa, T. Togashi, K. Tono, M. Yabashi, T. Ishikawa, J. Kim, R. Ryoo, J. Kim, H. Ihee and S.-i. Adachi, Nature, 518, 385-389 (2015). of the band ν1 + 2ν3 ← ν3. The spectrum is measured with cavity ring-down spectroscopy when the stabilized [2] Y. O. Jung, J. H. Lee, J. Kim, M. Schmidt, K. Moffat, V. Srajer and H. Ihee, Nat. Chem., 5, 212-220 (2013). CW-OPO idler beam pumps the J=17 rovibrational state of ν3. [3] H. Ihee, Acc. Chem. Res., 42, 356-366 (2009). References [4] M. Cammarata, M. Levantino, F. Schotte, P. A. Anfinrud, F. Ewald, J. Choi, A. Cupane, M. Wulff and H. [1] M. Vainio and L. Halonen, Physical Chemistry Chemical Physics 18, 4266 (2016). Ihee, Nat. Methods, 5, 881-887 (2008). [2] M. Vainio and J. Karhu, Optics Express 25, 4190 (2017). [5] H. Ihee, M. Lorenc, T. K. Kim, Q. Y. Kong, M. Cammarata, J. H. Lee, S. Bratos and M. Wulff, Science, [3] J. Karhu, M. Vainio, M. Metsälä, and L. Halonen, Optics Express 25, 4688 (2017). 309, 1223-1227 (2005).

24 2725 S-08

New Probes of Reaction Dynamics and Spectroscopy in Uniform Supersonic Flows

Arthur G. Suits

Department of Chemistry, University of Missouri Columbia MO 65211

We are pursuing a number of new directions in the study of chemical reaction dynamics and spectroscopy taking advantage of the unique properties of uniform supersonic flows. We have recently developed a chirped-pulse Fourier-transform microwave spectrometer coupled to a uniform supersonic flow opening new capabilities in product branching in reaction and photodissociation. We will show its application to obtain isomer-specific product detection in propargyl radical photodissociation as well as to bimolecular reactions, and discuss the unique capabilities and challenges of this instrument for reaction dynamics, kinetics, and spectroscopy. The high- performance supersonic flow we developed also represents an ideal environment in which to apply highly sensitive cw-cavity ring-down spectroscopy for detection of radicals and reaction intermediates and to study their reaction kinetics. We will introduce a new instrument taking advantage of this unique combination.

2826 H-04

New Probes of Reaction Dynamics and Spectroscopy in Real-time Imaging-based Spectroscopy of Nitrogen Dimer

Uniform Supersonic Flows a) b) b) a)c) Kenta Mizuse , Hikaru Sato , Haruki Ishikawa , and Yasuhiro Ohshima Arthur G. Suits a) Tokyo Institute of Technology, 2-12-1-W4-9 Ookayama, Meguro, Tokyo, Japan b) Department of Chemistry, University of Missouri Columbia MO 65211 Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, Japan c) Institute for Molecular Science, 38 Nishi-Gonaka, Myodaiji, Okazaki, Aichi, Japan

We are pursuing a number of new directions in the study of chemical reaction dynamics and Intermolecular interaction between nitrogen molecules is of great importance in atmospheric spectroscopy taking advantage of the unique properties of uniform supersonic flows. We have chemistry. This interaction induces dipole-allowed transitions of nitrogen in the infrared and far- recently developed a chirped-pulse Fourier-transform microwave spectrometer coupled to a uniform infrared region, and it affects the radiative energy balance of the Earth. To understand the nature of supersonic flow opening new capabilities in product branching in reaction and photodissociation. We such a two-body intermolecular interaction, spectroscopic study on molecular clusters in the gas phase will show its application to obtain isomer-specific product detection in propargyl radical is one of the powerful approaches. For the nitrogen clusters, however, due to their weak optical photodissociation as well as to bimolecular reactions, and discuss the unique capabilities and transitions between microwave to ultraviolet region, spectroscopic investigations have been rare. challenges of this instrument for reaction dynamics, kinetics, and spectroscopy. The high- Therefore, no direct information on the structure and intermolecular potential has been obtained. performance supersonic flow we developed also represents an ideal environment in which to apply In this study, we developed a new method highly sensitive cw-cavity ring-down spectroscopy for detection of radicals and reaction to probe the structure and dynamics of the intermediates and to study their reaction kinetics. We will introduce a new instrument taking nitrogen dimer by using a time-domain advantage of this unique combination. approach.1 We carried out an impulsive Raman excitation pump and Coulomb- explosion-imaging probe experiment. Because dipole transitions of the nitrogen dimer would be weak, we focused on the Raman process. Imaging probe gives us Figure 1. Time trace of the orientation function time-domain instantaneous structural/spatial information. rotational spectroscopic data. , where θ is the ejected + In the experiment, nitrogen dimer formed in a angle of the N2 ions with respect to the pump polarization. supersonic jet expansion was irradiated with a linearly polarized Raman pump pulse (820 nm, <1 ps, 0.5 mJ). Subsequent dynamics were probed with a time-delayed, circularly polarized probe pulse (407 nm, 80 fs, 0.3 mJ). Upon probe irradiation, + (N2)2 was doubly ionized, and N2 fragments were ejected due to the Coulomb repulsion. Spatial + 1 distribution of the N2 fragments was measured with a 2D spatial-slice ion imaging setup. Figure 1 shows the time-dependent orientation function of the nitrogen dimer obtained from the + observed real-time N2 ion image. When the intermolecular axis of the dimer is oriented along the pump pulse polarization, the value of this function becomes larger. Therefore, the time trace corresponds to the time-domain rotational spectroscopic data. In this trace, revival structures with a ~230 ps period can be seen. To obtain spectral information from this periodic trace, we carried out Fourier transformation (Figure 2). In the FT spectrum, several series of equally spaced peaks can be seen. Spacing between peaks (~4.4 GHz) agrees with the observed 230 ps period. The main series indicated by a solid line corresponds to the energy difference of the ΔJ = 2 Raman transition in the lowest state for the almost free-internal rotation of the N2 units. From the observed data, we determined a rotational constant (2.19 GHz), a centrifugal distortion (1.7 MHz), and Figure 2. Fourier transform of (t) (inset) intermolecular distance (4.05 Å) for the first time. Schematic of (N2)2 structure and the determined Other series can be assigned on the basis of nuclear spin intermolecular distance statistics (isomers) and Coriolis coupling. Details of our new experimental setup and analyses of spectral data will be presented.

References [1] K. Mizuse, K. Kitano, H. Hasegawa, Y. Ohshima, Sci. Adv. 1, e1400185 (2015).

26 2927 S-09

Unimolecular decay of Criegee intermediates to hydroxyl radical products*

Marsha I. Lester

Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323 USA

In the atmosphere, a dominant loss process for Criegee intermediates (R1R2COO) produced from alkene ozonolysis is also an important source of hydroxyl radicals. Recent studies [1-3] are focused on vibrational activation of methyl-substituted Criegee intermediates in the vicinity of the barrier for 1,4 hydrogen transfer that leads to OH products (Figure 1). The rate of appearance of OH radicals is revealed through direct time-domain measurements following vibrational activation of prototypical methyl-substituted Criegee intermediates under collision-free conditions. Complementary theoretical calculations predict the unimolecular decay rate for the Criegee intermediates in the vicinity of the barrier for 1,4 hydrogen transfer that leads to OH products. Tunneling through the barrier is shown to make a significant contribution to the decay rate. The results are extended to thermally averaged unimolecular decay of stabilized Criegee intermediates under atmospheric conditions.

Figure 1. Unimolecular decay pathway from the syn-CH3CHOO Criegee intermediate to OH radical products.

* This research was supported through the National Science Foundation under grant CHE-1362835.

References [1] Y. Fang, F. Liu, V. P. Barber, S. J. Klippenstein, A. B. McCoy, and M. I. Lester, J. Chem. Phys. 144, 061101 (2016). [2] Y. Fang, F. Liu, V. P. Barber, S. J. Klippenstein, A. B. McCoy, and M. I. Lester, J. Chem. Phys. 145, 234308 (2016). [3] Y. Fang, V. P. Barber, S. J. Klippenstein, A. B. McCoy, and M. I. Lester, J. Chem. Phys 146, 134307 (2017).

3028 S-10

Unimolecular decay of Criegee intermediates to hydroxyl Exploring Reactions of Criegee Intermediate CH2OO using a radical products* Step-Scan FTIR Spectrometer

Marsha I. Lester Yuan-Pern Leea) b)

Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323 USA a) Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001, Ta-Hsueh road, Hsinchu 30010, Taiwan b) In the atmosphere, a dominant loss process for Criegee intermediates (R1R2COO) produced from Institute of Atomic and Molecular Science, Academia Sinica, Taipei 10617, Taiwan alkene ozonolysis is also an important source of hydroxyl radicals. Recent studies [1-3] are focused Criegee intermediates were proposed to be produced in ozonolysis reactions of alkenes, which are on vibrational activation of methyl-substituted Criegee intermediates in the vicinity of the barrier for responsible for the non-photolytic production of OH, H2SO4, organic acids, and aerosols in the 1,4 hydrogen transfer that leads to OH products (Figure 1). The rate of appearance of OH radicals is atmosphere. These intermediates were detected directly in the gas phase only recently when a new revealed through direct time-domain measurements following vibrational activation of prototypical reaction scheme using UV photolysis of CH2I2 in O2 to generate the simplest Criegee intermediate methyl-substituted Criegee intermediates under collision-free conditions. Complementary theoretical CH2OO was employed [1]. The direct methods of production/detection have stimulated active calculations predict the unimolecular decay rate for the Criegee intermediates in the vicinity of the research on Criegee intermediates; our understanding of related important reactions in the atmosphere barrier for 1,4 hydrogen transfer that leads to OH products. Tunneling through the barrier is shown is becoming clarified [2]. The reaction of CH2OO with water was reported to be the most important to make a significant contribution to the decay rate. The results are extended to thermally averaged channel for the loss of CH2OO in the atmosphere. Three additional reactions CH2OO + SO2, CH2OO unimolecular decay of stabilized Criegee intermediates under atmospheric conditions. + HCOOH, and CH2OO + HNO3 were reported to be important because of their large rate coefficients,

(3.4−4.1)×10−11 [1], (1.1±0.1)×10‒10 [3], and (5.4±1.0)×10‒10 cm3 molecule−1 s−1 [4], respectively. Even though these reactions are rapid in the atmosphere, their impacts to atmospheric chemistry depend on the nature of the intermediates and products, which were little investigated in laboratories. We employed a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell to monitor time-resolved IR absorption of transient species produced upon UV irradiation of a flowing mixture. The reaction intermediates were identified according to quantum-chemically predicted reaction schemes, vibrational wavenumbers, IR intensities, and simulated rotational contours.

Upon 308-nm irradiation of a flowing mixture of CH2I2/O2/N2/SO2, four bands of CH2OO were observed, as reported previously [5]. At an initial reaction period, five new bands appeared at 1350, 1220, 1100, 940, and 880 cm−1. They are tentatively assigned to a cyclic adduct 1,3,2-dioxathietane- 2,2-dioxide. The band observed at 1391.5 cm−1 increased in a later period and is assigned to the degenerate ν3 stretching mode of SO3, which is the major product of the reaction CH2OO + SO2. The rotational contour of this band agrees satisfactorily with that simulated according to rotational parameters of SO3 predicted with the B3LYP/aug-cc-pVTZ method. We did not observe the products HCOOH (+ SO2) from the minor channel; an upper limit of 5% for the branching ratio of this channel was estimated.

Upon irradiation of a flowing mixture of CH2I2/O2/N2/HCOOH at 308 nm, six new bands appeared at 887, 925, 1025, 1115, 1169.5, 1341.5, and 1760 cm−1. They are assigned to the P5 conformer of the Figure 1. Unimolecular decay pathway from the syn-CH3CHOO Criegee intermediate to OH radical products. adduct hydroperoxymethyl formate (HPMF), but some contribution from the P6 conformer cannot be −11 3 excluded. The rate coefficient for formation of HPMF was determined to be (6±2)×10 cm * This research was supported through the National Science Foundation under grant CHE-1362835. −1 −1 ‒10 molecule s , slightly smaller than the previous report of (1.1±0.1)×10 [3]. At a later period, HPMF was converted to formic acid anhydride (FAN). The kinetics indicate that two processes involving two conformers of HPMF to form FAN + H2O at varied rates might be involved.

If time permit, we will also discuss the reaction of CH2OO + HNO3. Theoretical calculations were performed and the experimental observation of the spectrum agrees with that predicted for the References intermediate NO3CH2OOH. [1] Y. Fang, F. Liu, V. P. Barber, S. J. Klippenstein, A. B. McCoy, and M. I. Lester, J. Chem. Phys. 144, 061101 (2016). References [1] O.Welz et al. Science 335, 204 (2012). [2] Y. Fang, F. Liu, V. P. Barber, S. J. Klippenstein, A. B. McCoy, and M. I. Lester, J. Chem. Phys. 145, 234308 (2016). [2] Y.-P. Lee, J. Chem. Phys. 143, 020901 (2016). [3] Y. Fang, V. P. Barber, S. J. Klippenstein, A. B. McCoy, and M. I. Lester, J. Chem. Phys 146, 134307 [3] O. Welz et al. Angew. Chem. Int. Ed. 53, 4547 (2014). (2017). [4] E. S. Foreman, K. M. Kapnas, C. Murray, Angew. Chem. Int. Ed. 55, 10419 (2016). [5] Y.-T. Su, Y.-H. Huang, H. A. Witek, Y.-P. Lee, Science 340, 174 (2013).

28 3129 H-05

Reactions of Criegee intermediates at gas-aqueous interfaces

Shinichi Enami

National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Japan

Criegee intermediates (RR’COO biradicals/zwitterions, CIs) produced in the ozonation of gaseous olefins (e.g., terpenes) are versatile oxidizers and strong particle makers in the troposphere. At the large water vapor concentrations in the lower troposphere, it is expected that CIs will largely react with water dimers (H2O)2. However, the fates of CIs on the surface of atmospheric particles remain to be unveiled. In contrast with extensive studies on CIs chemistry in the gas-phase [1-5], the chemistry of CIs at the air-water interface relevant to that taking place on fog droplets, aqueous aerosol and thin water films have not been explored by direct experiments [6].

We report the first detection of intermediates and products from reactions of CIs with H2O, D2O, 18 H2 O, O3, a series of organic acids and alcohols on fresh surfaces of acetonitrile:water microjets containing sesquiterpenes (C15H24) exposed to O3(g) (Fig. 1) [7]. Our experiments probe the chemistry of Criegee intermediates produced by ozonolysis of unsaturated compounds in the interfacial layers of model aqueous organic aerosols for the first time. We provided mass-specific identification and established the progeny of products and intermediates in a flash reaction timeframe. We found that CIs can react at gas-aqueous interfaces with amphiphilic OH-containing species, in competition with interfacial water molecules (Fig. 2). We determined relative reaction rate for the reaction of CIs with these species at the interface. Molecular mechanisms on the CI reactions on the aqueous organic surface and the atmospheric implication will be discussed.

m/z 471 & 473 (in the case of cis-pinonic acid)

Fig.1 Schematic diagram of present Fig.2 Reaction mechanism of CIs + acids at gas-aqueous interfaces experimental setup

References [1] S. Hatakeyama and H. Akimoto, Res. Chem. Intermed., 20, 503-524 (1994). [2] M. Nakajima and Y. Endo, J. Chem. Phys. 139, 101103 (2013). [3] O. Welz et al. Angew. Chem. Int. Edit. 53, 4547-4550 (2014). [4] Y. P. Lee, J. Chem. Phys. 143, 020901 (2015). [5] N. M. Kidwell et al. Nat. Chem. 8, 509-514 (2016). [6] C. Q. Zhu et al. J. Am. Chem. Soc. 138, 11164-11169 (2016). [7] S. Enami and A. J. Colussi, J. Phys. Chem. Lett. 8, 1615-1623 (2017).

3230 S-11

+ + Reactions of Criegee intermediates at gas-aqueous interfaces Infrared spectroscopy of the (H2S)n and H (H2S)n clusters:

What is difference between H2S and H2O? Shinichi Enami

National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Japan Dandan Wang and Asuka Fujii

Criegee intermediates (RR’COO biradicals/zwitterions, CIs) produced in the ozonation of gaseous Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki-aza-aoba 6-3, Aoba, Sendai, Japan olefins (e.g., terpenes) are versatile oxidizers and strong particle makers in the troposphere. At the large water vapor concentrations in the lower troposphere, it is expected that CIs will largely react One of the important factors to characterize the nature of hydrogen-bonded (H-bonded) with water dimers (H2O)2. However, the fates of CIs on the surface of atmospheric particles remain structures of water is the H-bond coordination ability of water. A water molecule can be to be unveiled. In contrast with extensive studies on CIs chemistry in the gas-phase [1-5], the 4-coordenated at maximum (double donor - double acceptor), and this well-balanced and flexible chemistry of CIs at the air-water interface relevant to that taking place on fog droplets, aqueous coordination ability makes it possible to construct various and complicated H-bond network aerosol and thin water films have not been explored by direct experiments [6]. structures of water. Hydrogen sulfide, H2S, has the similar outer electron configuration to that of water. Therefore, the H-bond coordination ability of hydrogen sulfide is expected to be same as We report the first detection of intermediates and products from reactions of CIs with H2O, D2O, 18 water. On the other hand, the weak acidity of SH and the heavy atomic weight of sulfur suggest that H2 O, O3, a series of organic acids and alcohols on fresh surfaces of acetonitrile:water microjets various intermolecular interactions other than the H-bond can be competitive in hydrogen sulfide. containing sesquiterpenes (C15H24) exposed to O3(g) (Fig. 1) [7]. Our experiments probe the Comparison between the intermolecular structures of hydrogen sulfide and water would shed new chemistry of Criegee intermediates produced by ozonolysis of unsaturated compounds in the light on understanding of the long-discussed question, “what does make water special?” interfacial layers of model aqueous organic aerosols for the first time. We provided mass-specific Molecular clusters in the gas phase provide rich information on preferential identification and established the progeny of products and intermediates in a flash reaction intermolecular structures. While water clusters with the excess positive charge, i.e., radical cation timeframe. We found that CIs can react at gas-aqueous interfaces with amphiphilic OH-containing clusters (H O) + and protonated clusters H+(H O) , have been extensively studied, studies on the species, in competition with interfacial water molecules (Fig. 2). We determined relative reaction 2 n 2 n H S analogues, (H S) + and H+(H S) , have been surprising scarce. In the present study, we apply rate for the reaction of CIs with these species at the interface. Molecular mechanisms on the CI 2 2 n 2 n size-selective infrared (IR) spectroscopy to (H S) + and H+(H S) and determine their intermolecular reactions on the aqueous organic surface and the atmospheric implication will be discussed. 2 n 2 n structures with a help of high level ab initio calculations.

+ (H2S)n In radical ion clusters of molecules which have lone-pair electrons, spatial overlap of the non-bonding orbitals of the ionized and neutral molecules can result in formation of a hemibond (two center three electron (2c3e) bond). Such hemibond formation has been theoretically + predicted for (H2O)n . Its experimental confirmation, however, has never been succeeded because of + + the very efficient intracluster proton transfer reaction to form H3O OH(H2O)n-2. In (H2S)n , the preference of the hemibond structure over the proton transferred structure has been proposed since the weak acidity of the SH bond suppresses the intracluster proton transfer among H2S. We + measured IR spectra of (H2S)n (n = 36) in the SH stretch region. The spectral features clearly + demonstrate that the (H2S)2 dimer ion core is bound by a hemibond and this hemibonded core is stable to the first solvation shell formation. This is the first observation of the hemibond formation in protic molecules in the gas phase.

+ + + m/z 471 & 473 H (H2S)n It has been well-known that the Eigen (H3O ) and Zundel (H2O-H -OH2) type ion (in the case of cis-pinonic acid) + cores compete in H (H2O)n. In the H2S analogues, their size-selective IR spectra show that only the Eigen type (H S+) ion core is stably formed in the size range of n =39. This means the Fig.1 Schematic diagram of present Fig.2 Reaction mechanism of CIs + acids at gas-aqueous interfaces 3 experimental setup Grotthuss mechanism for the fast proton transfer is helpless in hydrogen sulfide. Moreover, after the completion of the first H-bonded solvation shell formation at n = 4, the second H-bonded shell is + not formed in H (H2S)n. Instead, a new solvation shell is bound by the charge-dipole interaction + and dispersion. The H3S ion core is finally surrounded by 7 molecules, and then the second + References H-bonded shell begins to form. This solvation process of H (H2S)n is very different from that of the + [1] S. Hatakeyama and H. Akimoto, Res. Chem. Intermed., 20, 503-524 (1994). corresponding H (H2O)n clusters. This result demonstrates that not only the H-bond coordination [2] M. Nakajima and Y. Endo, J. Chem. Phys. 139, 101103 (2013). ability but also the H-bond strength is the key for the nature of water. [3] O. Welz et al. Angew. Chem. Int. Edit. 53, 4547-4550 (2014). [4] Y. P. Lee, J. Chem. Phys. 143, 020901 (2015). References [5] N. M. Kidwell et al. Nat. Chem. 8, 509-514 (2016). [1] Dandan Wang and Asuka Fujii, Chem. Sci. 8, 2667 (2017). [6] C. Q. Zhu et al. J. Am. Chem. Soc. 138, 11164-11169 (2016). [2] Dandan Wang and Asuka Fujii, Phys. Chem. Chem. Phys. 19, 2036 (2017). [7] S. Enami and A. J. Colussi, J. Phys. Chem. Lett. 8, 1615-1623 (2017).

30 33 S-12

The Jahn-Teller Effect and Degeneracy Breaking in Free Radicals: Reconciling Theory and Experiment

Terry A. Miller

Department of Chemistry and Biochemistry, The Ohio State University, Columbus Ohio 43210, USA

Molecules that are Jahn-Teller active (JTA) are often difficult with which to deal from either an experimental or a theoretical point of view. Most electronic structure calculations assume the Born- Oppenheimer approximation and produce adiabatic potential energy surfaces (PES). Treating JTA molecules usually requires consideration of vibronic coupling between diabatic PESs. The spectra of such molecules are often much more complex than corresponding molecules that are well described by the BornOppenheimer approximation. Their vibrational structure can be quite irregular and their rotational structure often departs markedly from that expected for simple rigid rotors. Due to their open-shell nature JTA molecules are typically chemically reactive and experimentally elusive, so that obtaining good spectra can be challenging.

Fortunately much progress has been made in recent years both in the theoretical treatment of these molecules and the ability to obtain high quality vibrational and rotational spectra of these species. This talk will focus on comparing theoretical and experimental results for several JTA and pseudo- JTA molecules, for which we have obtained and analyzed vibronically and rotationally resolved spectra. These molecules include methoxy, CH3O and CD3O, and its asymmetrically substituted derivatives, CHnD3-nO and CHn(CH3)3-nO. Other examples include the nitrate radical, NO3, cyclopentadienyl, C5H5, and its asymmetrically deuterated derivatives C5HnD5-n. Experimental results will be compared to the results of state-of-the-art electronic structure calculations for these molecules.

3432 H-06

The Jahn-Teller Effect and Degeneracy Breaking in Free Ground and Excited States of Biological Radicals Radicals: Reconciling Theory and Experiment František Tureček Terry A. Miller a)Department of Chemistry, University of Washington, Seattle, WA, USA Department of Chemistry and Biochemistry, The Ohio State University, Columbus Ohio 43210, USA Chemical reactions creating radicals in biomolecules have been known for processes as diverse as Molecules that are Jahn-Teller active (JTA) are often difficult with which to deal from either an radiation damage and enzyme catalysis. The electronic nature of these radicals is often unknown and experimental or a theoretical point of view. Most electronic structure calculations assume the Born- has been a subject of speculations. We model biological radicals derived from proteins, DNA and Oppenheimer approximation and produce adiabatic potential energy surfaces (PES). Treating JTA RNA in the gas phase in the form of cation-radicals formed by methods of gas-phase ion chemistry molecules usually requires consideration of vibronic coupling between diabatic PESs. The spectra of [1]. In a typical experiment, cation-radicals are produced by electron transfer to or within such molecules are often much more complex than corresponding molecules that are well described biomolecular ions stored in a linear on trap. Oxidative electron transfer is accomplished by collision- by the BornOppenheimer approximation. Their vibrational structure can be quite irregular and their induced dissociation of ternary transition metal complexes incorporating a neutral biomolecule as a rotational structure often departs markedly from that expected for simple rigid rotors. Due to their ligand. Reductive electron transfer is accomplished by ion-ion reactions of the multiply charged open-shell nature JTA molecules are typically chemically reactive and experimentally elusive, so that biomolecular ion with an electron donor, typically, the fluoranthene anion. The ground electronic state obtaining good spectra can be challenging. of the biomolecular cation-radical is probed by collision-induced dissociation of the mass-selected ion, combined with Born-Oppenheimer molecular dynamics (BOMD) mapping of the potential Fortunately much progress has been made in recent years both in the theoretical treatment of these energy surface and calculations of unimolecular rate constants for dissociations. Excited electronic molecules and the ability to obtain high quality vibrational and rotational spectra of these species. states are investigated by UV-VIS photodissociation action spectroscopy [2,3] in the 210-700 nm This talk will focus on comparing theoretical and experimental results for several JTA and pseudo- range, which is aided by time-dependent density functional theory (TD-DFT) and equation-of-motion JTA molecules, for which we have obtained and analyzed vibronically and rotationally resolved coupled cluster (EOM-CCSD) calculations of excitation energies and transition moments [4]. spectra. These molecules include methoxy, CH3O and CD3O, and its asymmetrically substituted derivatives, CHnD3-nO and CHn(CH3)3-nO. Other examples include the nitrate radical, NO3, Recently, TD-DFT calculations have been coupled with vibrational analysis to produce vibronically cyclopentadienyl, C5H5, and its asymmetrically deuterated derivatives C5HnD5-n. Experimental results broadened UV-VIS spectra for direct comparison with experimental photodissociation action spectra will be compared to the results of state-of-the-art electronic structure calculations for these molecules. [3]. Examples will be presented of recent applications of the new experimental and computational methods to generate peptide and nucleic acid radicals in the gas phase and investigate their conformations and electronic structure.

Figure: UV-VIS photodissociation action spectrum of 2'-deoxyadenine dinucleotide cation radicals showing wavelength- and mass-resolved photodissociation channels.

References [1] Tureček, F.; Julian, R. R. Chem. Rev. 113, 6691-6733 (2013). [2] Viglino. E.; Shaffer, C. J.; Tureček, F. Angew. Chem. Int. Ed. 55, 7469-7473 (2016). [3] Nguyen, H. T. H; Shaffer, C. J.; Pepin, R.; Turecek, F. J. Phys. Chem. Lett. 6, 4722-4727 (2015) [4] Lesslie, M.; Lawler, J. T.; Dang, A.; Korn, J. A.; Bím, D.; Steinmetz, V.; Maitre, P.; Tureček F.; Ryzhov, V. ChemPhysChem 18, (2017) DOI:10.1002/cphc.201700281.

32 3533 S-13

Direct mapping of the key feature of the potential energy surface

Kopin Liua), Huilin Pana), and Fengyan Wang a),b)

a) Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan 10617. b) Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China.

Within the Born-Oppenheimer approximation, the geometry and property of a molecule are governed by the electronic structure or the potential energy surface (PES); likewise, the reactivity of a chemical reaction by the intermolecular interaction. Traditionally, what experimentalists can measure is the spectroscopy, the rate constant or cross section etc. ‒ not the PES itself. Theorists then need to solve the nuclear quantum dynamics (QD) on a given PES. By simulating the experimentally measured quantity, the theory-experiment comparison can be made to validate the PES. As we move toward larger chemical systems, it becomes increasingly more difficult to calculate accurate PES and to perform exact QD in full dimensionality. Some approximate methods such as the quasiclassical trajectory or the reduced dimensionality QD are often employed, resulting in some uncertainty on the discrepancy being from the deficiencies of the PES used or from the dynamics approximations. It is therefore highly desirable to develop a new way of thinking or experimental approach that is capable of direct determination of the key features of the PES for comparison.

Here, we will present two such examples. First, using the benchmark reaction of Cl + CHD3(v1 = 1) as an example, we show how to map the angle-dependent barrier directly from a polarized scattering experiment. The deduced bend potential of the Cl‒H‒C configuration at the transition state agrees with ab initio calculated ones, validating the method [1]. Second, we will present a different set of experiments on the ground-state reaction of F + CH3D, which suggests the possibility of inferring the well depth of the vibrationally adiabatic well ‒ one of the key features of the PES in characterizing the quantum dynamical resonances ‒ from the experimentally sighted ‘reactive rainbow’ [2].

References [1] H. Pan, F. Wang, G. Czako, and K. Liu, Nat. Chem. (in revision, 2017). [2] H. Pan and K. Liu, J. Phys. Chem. A 120, 6712-6718 (2016).

3634 S-14

Direct mapping of the key feature of the potential energy The strange world of nonadiabatic tunneling - The effect of surface geometric phase and diagonal Born-Oppenheimer correction

Kopin Liua), Huilin Pana), and Fengyan Wang a),b) Hua Guoa), Changjian Xiea), and David R. Yarkonyb)

a) a) Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica, Taipei, Taiwan 10617. Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131 b) Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China. b)Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218

Within the Born-Oppenheimer approximation, the geometry and property of a molecule are governed Within the familiar Born-Oppenheimer approximation, nuclear dynamics, including tunneling, is by the electronic structure or the potential energy surface (PES); likewise, the reactivity of a chemical often envisioned to occur on an adiabatic potential energy surface. However, this single-state adiabatic reaction by the intermolecular interaction. Traditionally, what experimentalists can measure is the picture needs be reconsidered if a conical intersection (CI) is present, even when the energy is spectroscopy, the rate constant or cross section etc. ‒ not the PES itself. Theorists then need to solve nominally much lower than the CI. This is because the presence of CI introduces two additional terms the nuclear quantum dynamics (QD) on a given PES. By simulating the experimentally measured into the adiabatic Hamiltonian, namely the geometric phase (GP) and diagonal Born-Oppenheimer quantity, the theory-experiment comparison can be made to validate the PES. As we move toward correction (DBOC). The GP, which is a by-product of the Born-Oppenheimer separation of electronic larger chemical systems, it becomes increasingly more difficult to calculate accurate PES and to and nuclear motion, can qualitatively alter the behavior of the system. In this talk, we discuss the perform exact QD in full dimensionality. Some approximate methods such as the quasiclassical nonadiabatic tunneling dynamics in the photodissociation of phenol near a CI between the S1 and S2 trajectory or the reduced dimensionality QD are often employed, resulting in some uncertainty on the states. It is shown that the inclusion of GP in the one-state adiabatic Hamiltonian leads to interference discrepancy being from the deficiencies of the PES used or from the dynamics approximations. It is between tunneling “trajectories” on the two sides of the CI, resulting in either retardation (destructive therefore highly desirable to develop a new way of thinking or experimental approach that is capable interference) or enhancement (constructive interference) of the tunneling rate. These interference of direct determination of the key features of the PES for comparison. effects manifest in the tunneling wavefunction as the appearance or disappearance of a node.

Here, we will present two such examples. First, using the benchmark reaction of Cl + CHD3(v1 = 1) as an example, we show how to map the angle-dependent barrier directly from a polarized scattering experiment. The deduced bend potential of the Cl‒H‒C configuration at the transition state agrees with ab initio calculated ones, validating the method [1]. Second, we will present a different set of experiments on the ground-state reaction of F + CH3D, which suggests the possibility of inferring the well depth of the vibrationally adiabatic well ‒ one of the key features of the PES in characterizing the quantum dynamical resonances ‒ from the experimentally sighted ‘reactive rainbow’ [2].

References [1] C. Xie, C., J. Ma, X. Zhu, D. R. Yarkony, D. Xie, H. Guo, Nonadiabatic tunneling in photodissociation of phenol. J. Am. Chem. Soc. 138, 7828-7831, (2016). References [2] C. Xie, D. R. Yarkony, H. Guo, Nonadiabatic tunneling via conical intersections and the role of the [1] H. Pan, F. Wang, G. Czako, and K. Liu, Nat. Chem. (in revision, 2017). geometric phase. Phys. Rev. A 95, 022104 (2017). [3] C. Xie, B. K. Kendrick, D. R. Yarkony, H. Guo, Constructive and destructive Interference in nonadiabatic [2] H. Pan and K. Liu, J. Phys. Chem. A 120, 6712-6718 (2016). tunneling via conical intersections. J. Chem. Theo. Comput. 13, 1902-1910 (2017).

34 3735 H-07

Atmospheric oxidation of NH3 by NO3 and OH radicals. Proton coupled electron transfer versus Hydrogen atom transfer reaction mechanisms.

Josep M. Anglada

Departament de Química Biològica i Modelització Molecular, IQAC-CSIC, c/ Jordi Girona, 18 E-08034 Barcelona, Spain e-mail : [email protected]

Ammonia is the most abundant alkaline gaseous species in the troposphere and constitutes the third most abundant nitrogen compound in the atmosphere. It is emitted to the atmosphere from + antropogenic and biogenic sources and the main sinks involve dry and wet deposition forming NH4 contributing to the formation of aerosols. In gas phase ammonia can also be oxidized by OH and NO3 radicals (reactions 1 and 2), which have estimated to contribute to a nonsignificant ~3% to the removal of NH3 in the troposphere

NH3 + OH → NH2 + H2O (1)

NH3 + NO3 → NH2 + HNO3 (2)

Both reaction 1 and 2 involve the abstraction of one hydrogen atom from ammonia by the radical but each reaction takes place in a very different manner. In reaction 1 the hydroxyl radical abstracts one hydrogen atom of NH3 by an hydrogen atom transfer mechanism (hat), which involves a concerted breaking and making of covalent bonds (see Figure 1a). However, reaction 2 takes place through a proton coupled electron transfer process (pcet) in which one electron is transferred from the lone pair of NH3 to the NO3 radical and, simultaneously, one proton is transferred between both moieties (see Figure 1b). The different reaction mechanisms, the computed rate constants and the effect of water vapor on reactions 1 and 2 will be discussed.

Fig. 1a: hat Fig. 1b: pcet

Figure 1: Electronic features for the oxidation of NH3 by OH through an hydrogen atom transfer mechanism (fig 1a), and for the oxidation of NH3 by NO3 through a proton coupled electron transfer mechanism (fig 1b).

References [1] M.A.H. Khan, R.G. Derwent, K. Lyons, J.M. Anglada, J.S. Francisco, C.J. Percival, D.E. Shallcross. Submitted for publication [2] S. Olivella, J. M. Anglada, A. Solé, J. M. Bofill. Chem. Eur. J., 2004, 10, 3404. [3] J. M. Anglada, J. Am. Chem. Soc, 2004, 126, 9809. [4] J. González, J. M. Anglada, J. Phys. Chem. A, 2010, 114,9151 [5] J. M. Anglada, S. Olivella, A. Solé ,J. Am. Chem. Soc. 2014, 136, 6834

3836 S-15

Atmospheric oxidation of NH3 by NO3 and OH radicals. Proton Probing Quantum Dynamics of Chemical Reactions with High coupled electron transfer versus Hydrogen atom transfer Resolution H-atom Rydberg Tagging and Velocity Map Imaging reaction mechanisms. Xueming Yang Josep M. Anglada Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Department of Chemical Physics, University of Science and Technology of China Departament de Química Biològica i Modelització Molecular, IQAC-CSIC, c/ Jordi Girona, 18 E-08034 Barcelona, Spain e-mail : [email protected] Quantized transition states and reaction resonances in chemical reactions have been the central topics in the study of chemical reaction dynamics. In the recent years, we have made significant progresses Ammonia is the most abundant alkaline gaseous species in the troposphere and constitutes the third in the study of quantum dynamics of a few triatomic benchmark reactions using quantum-state most abundant nitrogen compound in the atmosphere. It is emitted to the atmosphere from + resolved crossed molecular beams scattering method, in combination with accurate quantum antropogenic and biogenic sources and the main sinks involve dry and wet deposition forming NH4 dynamics theory. Experimentally, we have developed state-of-art crossed molecular beam techniques contributing to the formation of aerosols. In gas phase ammonia can also be oxidized by OH and NO3 that allow us to probe resonance structures in the triatomic reactions through H-atom Rydberg tagging radicals (reactions 1 and 2), which have estimated to contribute to a nonsignificant ~3% to the and velocity map imaging. Theoretically, we have developed the most accurate potential energy removal of NH3 in the troposphere surfaces for accurate quantum dynamics studies to provide deep dynamics insights of these chemical reactions at the most fundamental level. In this talk, I will provide an overview of the experimental NH3 + OH → NH2 + H2O (1) and theoretical results on the three benchmark reaction systems: H+H2, F+H2, and Cl+H2. Through the combined experimental and theoretical efforts, we have shown that energy dependent backward NH3 + NO3 → NH2 + HNO3 (2) scattering differential cross section measurement can provide clear spectroscopic information on the Both reaction 1 and 2 involve the abstraction of one hydrogen atom from ammonia by the radical but quantum structures in the transition state region. The nature of the resonances observed in the F+H2 each reaction takes place in a very different manner. In reaction 1 the hydroxyl radical abstracts one and Cl+H2 will be also discussed in this talk. Through the studies of reaction resonances in these systems, we found that resonances can exist in many chemical reactions, especially in the reactions hydrogen atom of NH3 by an hydrogen atom transfer mechanism (hat), which involves a concerted breaking and making of covalent bonds (see Figure 1a). However, reaction 2 takes place through a of vibrationally excited species. In addition, through high angular resolution velocity map imaging proton coupled electron transfer process (pcet) in which one electron is transferred from the lone pair studies, we can now provide detailed understanding of the quantum dynamics of chemical reactions. of NH3 to the NO3 radical and, simultaneously, one proton is transferred between both moieties (see Figure 1b). The different reaction mechanisms, the computed rate constants and the effect of water vapor on reactions 1 and 2 will be discussed.

Fig. 1a: hat Fig. 1b: pcet

Figure 1: Electronic features for the oxidation of NH3 by OH through an hydrogen atom transfer mechanism (fig 1a), and for the oxidation of NH3 by NO3 through a proton coupled electron transfer mechanism (fig 1b).

References [1] M.A.H. Khan, R.G. Derwent, K. Lyons, J.M. Anglada, J.S. Francisco, C.J. Percival, D.E. Shallcross. Submitted for publication [2] S. Olivella, J. M. Anglada, A. Solé, J. M. Bofill. Chem. Eur. J., 2004, 10, 3404. [3] J. M. Anglada, J. Am. Chem. Soc, 2004, 126, 9809. [4] J. González, J. M. Anglada, J. Phys. Chem. A, 2010, 114,9151 [5] J. M. Anglada, S. Olivella, A. Solé ,J. Am. Chem. Soc. 2014, 136, 6834

36 3937 S-16

Direct Time-Resolved Studies of Radical Intermediates in Gas- Phase Oxidation Reactions

Leonid Sheps, Ivan O. Antonov, Justin Kwok, Judit Zádor, Brandon Rotavera, Ewa Papajak, David L. Osborn, Craig A. Taatjes

Combustion Research Facility, Sandia National Laboratories, Livermore, 94551, USA

Gas-phase oxidation of organic compounds involves large networks of coupled temperature- and pressure-dependent reactions, occurring on complex potential energy surfaces with multiple energy barriers and metastable intermediate species. It starts when a carbon-centered radical (R) reacts with O2 to form an oxygen-centered peroxy radical (ROO), which can in turn decompose to products or undergo an internal H-atom shift to another substituted carbon-centered radical, QOOH. QOOH can also decompose or react with O2 to form a second peroxy radical, OOQOOH, leading potentially to further isomerization, dissociation, or O2 addition. This general framework of competing decomposition and oxidation reactions plays a central role in diverse environments, ranging from the Earth’s atmosphere to low-temperature (T < 1000 K) combustion. In atmospheric chemistry, successive H-atom transfers, followed by O2 additions, result in the growth of highly oxygenated low-volatility organic compounds, with implications to the formation and aging of aerosols and ultimately to climate modeling [1]. In combustion, second-O2 addition (QOOH + O2) reactions lead to radical chain branching that eventually produces ignition [2][3]. Many advanced compression- ignition engine designs rely on fuel autoignition in the low-T regime, and fundamental understanding of oxidation chemistry is therefore important in optimizing their performance.

As part of the joint Argonne-Sandia High-Pressure Combustion Chemistry program, we have developed novel spectroscopic and mass spectrometric methods, aimed at direct time-resolved detection of key radicals (OH, HO2, R, ROO, QOOH, and OOQOOH) and stable reaction end- products at elevated temperatures and pressures. This talk will highlight two recent applications of these new experimental tools to various aspects of hydrocarbon oxidation chemistry. I will present the results of laser-induced fluorescence OH detection in the OH + 2-butene reaction at P = 1 – 20 bar, which probed (among other processes) the formation and decomposition kinetics of 3-hydroxy- 2-butyl intermediates – primary radical species in the oxidation of 2-butanol. I will also present a mass spectrometric study of tetrahydrofuran (THF) oxidation at P = 0.013 – 3 bar, which revealed the mechanism of the first- and second-O2 addition reactions. Many of the features of this complex mechanism reflect the influence of molecular structure on the reactivity of THF and have broad consequences, e.g. in the autoignition of ethers. Such structural and functional-group effects may also direct the oxidation of other species in the troposphere or in combustion, and I will briefly explore the extent of possible implications and frontiers for future work.

This work is supported by the Division of Chemical Sciences, Geosciences, and Biosciences, the Office of Basic Energy Sciences, the U.S. Department of Energy through the Argonne-Sandia Consortium on High-Pressure Combustion Chemistry. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525

References [1] J. D. Crounse, L. B. Nielsen, S. Jørgensen, H. G. Kjaergaard and P. O. Wennberg, J. Phys. Chem. Lett., 4, 3513-3520, (2013). [2] Z. Wang, L. Zhang, K. Moshammer, D. M. Popolan-Vaida, V. S. B. Shankar, A. Lucassen, C. Hemken, C. A. Taatjes, S. R. Leone and K. Kohse-Höinghaus, Combust. Flame, 164, 386-396, (2016). [3] J. Zádor, C. A. Taatjes and R. X. Fernandes, Prog. Ener. Comb. Sci., 37, 371-421, (2011).

4038 S-17

Direct Time-Resolved Studies of Radical Intermediates in Gas- Radical Reaction Mechanisms for Organic Nitrogen Compounds Phase Oxidation Reactions in the Atmosphere

Leonid Sheps, Ivan O. Antonov, Justin Kwok, Judit Zádor, Brandon Rotavera, Gabriel da Silvaa) Ewa Papajak, David L. Osborn, Craig A. Taatjes a) The University of Melbourne, Parkville 3010 Victoria, Australia Combustion Research Facility, Sandia National Laboratories, Livermore, 94551, USA Amines are significant trace atmospheric components, released in biomass burning, animal Gas-phase oxidation of organic compounds involves large networks of coupled temperature- and husbandry, and a range of industrial activities. Atmospheric amines contribute to aerosol pressure-dependent reactions, occurring on complex potential energy surfaces with multiple energy nucleation, and are potential precursors to toxic nitrogenated compounds (e.g. nitrosamines) and barriers and metastable intermediate species. It starts when a carbon-centered radical (R) reacts with potent global warming agents (e.g. N2O). Surprisingly little is known, however, about the O2 to form an oxygen-centered peroxy radical (ROO), which can in turn decompose to products or atmospheric oxidation chemistry of amines. We have applied ab initio calculations coupled with undergo an internal H-atom shift to another substituted carbon-centered radical, QOOH. QOOH can statistical (RRKM theory / master equation) kinetic modelling to investigate key processes in the also decompose or react with O2 to form a second peroxy radical, OOQOOH, leading potentially to photochemical oxidation of amines. The initial stage of amine degradation in the atmosphere is further isomerization, dissociation, or O2 addition. This general framework of competing known to be H atom abstraction by the OH radical, with experimentally detected products being decomposition and oxidation reactions plays a central role in diverse environments, ranging from the • • mainly α-amino alkyl and aminyl radicals (for instance, CH3N H and CH2NH2 from methylamine; Earth’s atmosphere to low-temperature (T < 1000 K) combustion. In atmospheric chemistry, see figure below), and our recent work has focused on the further reaction chemistry of these successive H-atom transfers, followed by O2 additions, result in the growth of highly oxygenated species. H low-volatility organic compounds, with implications to the formation and aging of aerosols and N N + NO H C N - H2O ultimately to climate modeling [1]. In combustion, second-O2 addition (QOOH + O2) reactions lead H3C N 3 N to radical chain branching that eventually produces ignition [2][3]. Many advanced compression- NH [2] [2] H2C N O OH ignition engine designs rely on fuel autoignition in the low-T regime, and fundamental understanding H3C of oxidation chemistry is therefore important in optimizing their performance. + NO + OH - NO2 + O2 NH2 + OH - O OO NH2 H NH2 - HO2 H C - H2O HN C O 3 + O2 C C As part of the joint Argonne-Sandia High-Pressure Combustion Chemistry program, we have H2 H [3] developed novel spectroscopic and mass spectrometric methods, aimed at direct time-resolved detection of key radicals (OH, HO2, R, ROO, QOOH, and OOQOOH) and stable reaction end- NH2 H2C products at elevated temperatures and pressures. This talk will highlight two recent applications of + O2 - these new experimental tools to various aspects of hydrocarbon oxidation chemistry. I will present HO2 [1] the results of laser-induced fluorescence OH detection in the OH + 2-butene reaction at P = 1 – 20 NH bar, which probed (among other processes) the formation and decomposition kinetics of 3-hydroxy- H2C 2-butyl intermediates – primary radical species in the oxidation of 2-butanol. I will also present a Figure 1: Prototypical reaction scheme for the photochemical oxidation of an amine (methylamine), mass spectrometric study of tetrahydrofuran (THF) oxidation at P = 0.013 – 3 bar, which revealed highlighting new pathways to imines [1], alkyldiazohydroxides / diazoalkanes [2], and isocyanates [3]. the mechanism of the first- and second-O2 addition reactions. Many of the features of this complex mechanism reflect the influence of molecular structure on the reactivity of THF and have broad consequences, e.g. in the autoignition of ethers. Such structural and functional-group effects may The α-amino alkyl radical products of amine oxidation are classically expected to react with O2 also direct the oxidation of other species in the troposphere or in combustion, and I will briefly to produce amides, however we have shown that imine formation is a dominant process [1]. explore the extent of possible implications and frontiers for future work. Aminyl radicals, on the other hand, are unreactive with O2 and predominantly associate with NO

and NO to yield nitrosamines and nitramines. We have also revealed that aminyl radical reactions 2 This work is supported by the Division of Chemical Sciences, Geosciences, and Biosciences, the Office of Basic with NO can lead to the production of toxic alkyldiazohydroxides and diazoalkanes [2]. Finally, the Energy Sciences, the U.S. Department of Energy through the Argonne-Sandia Consortium on High-Pressure OH radical initiated oxidation of a series of amides has been considered, in conjunction with smog Combustion Chemistry. Sandia National Laboratories is a multimission laboratory managed and operated by chamber experiments. Formyl amides are shown to efficiently produce toxic isocyanates, via National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract unimolecular peroxyl radical chemistry [3]. Larger primary amides, however, predominantly DE-NA0003525 generate formyl amides, which are suspected to involve new alkoxyl radical chemistry.

References [1] G. da Silva, B. B. Kirk, C. Lloyd, A. J. Trevitt, S. J. Blanksby, J. Phys. Chem. Lett., 3, 805-811 (2012). [1] J. D. Crounse, L. B. Nielsen, S. Jørgensen, H. G. Kjaergaard and P. O. Wennberg, J. Phys. Chem. Lett., 4, 3513-3520, [2] G. da Silva, Environ. Sci. Technol. 2013, 47, 7766-7772 (2013). (2013). [3] N. Borduas, G. da Silva, J. G. Murphy, J. P. D. Abbatt, J. Phys. Chem. A 2015, 119, 4298-4308 (2015). [2] Z. Wang, L. Zhang, K. Moshammer, D. M. Popolan-Vaida, V. S. B. Shankar, A. Lucassen, C. Hemken, C. A. Taatjes, S. R. Leone and K. Kohse-Höinghaus, Combust. Flame, 164, 386-396, (2016). [3] J. Zádor, C. A. Taatjes and R. X. Fernandes, Prog. Ener. Comb. Sci., 37, 371-421, (2011).

38 41 H-08

HO2 yield in the reaction of different peroxy radicals with OH radicals

Christa Fittschen, Emmanuel Assaf, and Coralie Schoemacker

CNRS - University Lille,Bât. C11, Cité Scientifique,Villeneuve d’Ascq, France

Peroxy radicals, RO2, are key species in the atmosphere. They are formed from a reaction of OH radicals with hydrocarbon:

RH + OH + O2 → RO2 + H2O

In polluted environments, RO2 radicals react predominantly with NO, leading to formation of NO2 and eventually through photolysis of NO2 to formation of O3. At low NOx concentrations such as in the marine boundary layer or the background troposphere, the lifetime of RO2 radicals increases and other reaction pathways become competitive. Atmospheric chemistry models have considered until recently only the self- and cross reaction with other RO2 radicals or with HO2 radicals as the major fate for RO2 radicals under low NOx conditions. Recently, the rate constants for the reaction of peroxy radicals with OH radicals RO2 + OH → products has been measured for CH3O2 [1, 2] and C2H5O2 [3] and it was shown to become competitive to other sinks [4]. However, in order to evaluate the impact of this so far neglected sink for peroxy radicals on the composition of remote atmospheres, the reaction products must be known. A recently improved experimental set-up combining laser photolysis with two simultaneous cw-CRDS detections in the near IR allowing for a time resolved, absolute quantification of OH and RO2 radicals has been used for a further investigation of this class of reactions. High-repetition rate LIF is used for determining relative OH profiles.

For CH3O2 radicals, HO2 has been determined as major product recently [5]. Currently, we study the next larger perxoy, C2H5O2, using different radical precursors (C2H5I, (COCl)2/C2H6, XeF2/C2H6) and also deuterated C2D5I in order to elucidate the product yield. Preliminary results show a much lower HO2 yield for C2H5O2 compared to CH3O2. The most recent results will be presented at the conference.

References [1] A. Bossolasco, E. Faragó, C. Schoemaecker, and C. Fittschen, CPL, 593, 7, (2014). [2] E. Assaf, B. Song, A. Tomas, C. Schoemaecker, C. Fittschen, JPC A, 120, 8923 (2016) [3] Eszter Faragó, Coralie Schoemaecker, Bela Viskolcz, and Christa Fittschen, CPL, 619, 196, (2015). [4] Christa Fittschen, Lisa Whalley, and Dwayne Heard, EST, 118, 7700, (2014). [5] E. Assaf, L. Sheps, L. Whalley, D. Heard, A. Tomas, C. Schoemaecker, C. Fittschen, EST, 51, 2170 (2017)

4240 S-18

HO2 yield in the reaction of different peroxy radicals with OH Ultrafast chemical dynamics in solutions radicals Majed Chergui Christa Fittschen, Emmanuel Assaf, and Coralie Schoemacker Lab. of Ultrafast Spectroscopy (LSU) and Lausanne Centre for Ultrafast Science (LACUS) CNRS - University Lille,Bât. C11, Cité Scientifique,Villeneuve d’Ascq, France Ecole Polytechnique Fédérale de Lausanne ISIC, FSB, Station 6 CH-1015 Lausanne, Switzerland Peroxy radicals, RO2, are key species in the atmosphere. They are formed from a reaction of OH radicals with hydrocarbon: In this talk, I will present case studies of the photophysical and photochemical dynamics of

RH + OH + O2 → RO2 + H2O coordination chemistry complexes using a toolbox of ultrafast methods: transient absorption from the infrared to the deep-ultraviolet, X-ray absorption and emission spectroscopy and photoelectron In polluted environments, RO2 radicals react predominantly with NO, leading to formation of NO2 spectroscopy of liquid solutions. The systems that will be discussed include: ferric Iron hexacyanide and eventually through photolysis of NO2 to formation of O3. At low NOx concentrations such as in showing an impulsive electronic-to-vibrational energy conversion,[1] ferrous Iron hexacyanide the marine boundary layer or the background troposphere, the lifetime of RO2 radicals increases and showing the mechanism of photoaquation[2] and diplatinum complexes with an emphasis on other reaction pathways become competitive. Atmospheric chemistry models have considered until transfer of vibrational coherence in intersystem crossing events.[3] Implications for the study of recently only the self- and cross reaction with other RO2 radicals or with HO2 radicals as the major sensitized solar cells and perspectives for studies at Free Electron lasers will be discussed. fate for RO2 radicals under low NOx conditions. Recently, the rate constants for the reaction of peroxy radicals with OH radicals RO2 + OH → products References [1] Reinhard, M., et al., Journal of the American Chemical Society, 2017. 139(21): p. 7335-7347. has been measured for CH3O2 [1, 2] and C2H5O2 [3] and it was shown to become competitive to other [2] Ojeda, J., et al., Physical Chemistry Chemical Physics, 2017,19: p. 17052-17062 sinks [4]. However, in order to evaluate the impact of this so far neglected sink for peroxy radicals [3] Monni, R., et al., Nature Chemistry, 2017. under review. on the composition of remote atmospheres, the reaction products must be known. A recently improved experimental set-up combining laser photolysis with two simultaneous cw-CRDS detections in the near IR allowing for a time resolved, absolute quantification of OH and RO2 radicals has been used for a further investigation of this class of reactions. High-repetition rate LIF is used for determining relative OH profiles.

For CH3O2 radicals, HO2 has been determined as major product recently [5]. Currently, we study the next larger perxoy, C2H5O2, using different radical precursors (C2H5I, (COCl)2/C2H6, XeF2/C2H6) and also deuterated C2D5I in order to elucidate the product yield. Preliminary results show a much lower HO2 yield for C2H5O2 compared to CH3O2. The most recent results will be presented at the conference.

References [1] A. Bossolasco, E. Faragó, C. Schoemaecker, and C. Fittschen, CPL, 593, 7, (2014). [2] E. Assaf, B. Song, A. Tomas, C. Schoemaecker, C. Fittschen, JPC A, 120, 8923 (2016) [3] Eszter Faragó, Coralie Schoemaecker, Bela Viskolcz, and Christa Fittschen, CPL, 619, 196, (2015). [4] Christa Fittschen, Lisa Whalley, and Dwayne Heard, EST, 118, 7700, (2014). [5] E. Assaf, L. Sheps, L. Whalley, D. Heard, A. Tomas, C. Schoemaecker, C. Fittschen, EST, 51, 2170 (2017)

40 43 S-19

Imaging the photodissociation of small hydrocarbon radicals

Luis Bañaresa)

a) Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain

The photochemistry of small hydrocarbon radicals is of great importance in fundamental processes in Chemistry, such as atmospheric chemistry, hydrocarbon combustion, formation of complex hydrocarbons in the interstellar medium, troposphere chemistry or chemical vapour deposition for diamond growth. Recently we have studied the photodissociation dynamics of the methyl (CH3) radical from the 3s and 3pz Rydberg states by one and two-photon excitation, respectively, using a combination of femtosecond [1] and nanosecond [2] laser pulses and the velocity map and slice ion imaging techniques. A great deal of details about the time-resolved predissociation dynamics of the 3pz state and of the photodissociation dynamics to the final photofragments CH2 + H from the two excited states, have been obtained and the experimental results have been explained by high level ab initio calculations of the potential energy surfaces involved in the photodissociation process [1-3]. More recently, we have studied the photodissociation dynamics of hot and cold ethyl (C2H5) radicals from the 3p Rydberg state by absorption of one-photon in the region of 200 nm. Velocity map imaging of both the H-atoms (C-H bond cleavage) and the methyl radicals (C-C bond cleavage) have been measured. A full account of the most interesting results will be given at the Conference.

References [1] G. Balerdi, J. Woodhouse, A. Zanchet, R. de Nalda, M. L. Senent, A. García-Vela, L. Bañares, Phys. Chem. Chem. Phys., 18, 110 (2016). [2] S. Marggi Poullain, D. V. Chicharro, A. Zanchet, M. G. González, L. Rubio-Lago, M. L. Senent, A. García- Vela, L. Bañares, Phys. Chem. Chem. Phys., 18, 17054 (2016). [3] Zanchet, L. Bañares, M. L. Senent, A. García-Vela, Phys. Chem. Chem. Phys., 18, 33195 (2016).

4442 H-09

Imaging the photodissociation of small hydrocarbon radicals Full observation of cascaded radiationless transitions from  a) S2( ) state of pyrazine by ultrafast VUV photoelectron imaging Luis Bañares Takuya Horio, and Toshinori Suzuki a) Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo- ku, Kyoto 606-8502, Japan The photochemistry of small hydrocarbon radicals is of great importance in fundamental processes in Chemistry, such as atmospheric chemistry, hydrocarbon combustion, formation of complex A photoexcited molecule undergoes a variety of photophysical and photochemical processes hydrocarbons in the interstellar medium, troposphere chemistry or chemical vapour deposition for simultaneously or sequentially, and the molecule ultimately relaxes to the ground electronic state or diamond growth. Recently we have studied the photodissociation dynamics of the methyl (CH3) undergoes chemical reactions. Time-resolved photoelectron imaging (TRPEI) [1] enables full radical from the 3s and 3pz Rydberg states by one and two-photon excitation, respectively, using a observation of these photo-induced dynamics, because photoionization can be induced from any part combination of femtosecond [1] and nanosecond [2] laser pulses and the velocity map and slice ion of the potential energy surfaces (PESs). However, photoionization from low-lying excited states and imaging techniques. A great deal of details about the time-resolved predissociation dynamics of the the ground electronic state requires high probe photon energy in the vacuum ultraviolet (VUV) 3pz state and of the photodissociation dynamics to the final photofragments CH2 + H from the two wavelength region, and it was difficult to generate intense femtosecond VUV laser pulses. We have excited states, have been obtained and the experimental results have been explained by high level ab developed filamentation four-wave mixing (FWM) in rare gas [2,3] for routine generation of sub-20 initio calculations of the potential energy surfaces involved in the photodissociation process [1-3]. fs VUV pulses, and we applied TRPEI using 9.3 eV probe photon to the benchmark system of More recently, we have studied the photodissociation dynamics of hot and cold ethyl (C2H5) radicals pyrazine (C4N2H4) [4]. from the 3p Rydberg state by absorption of one-photon in the region of 200 nm. Velocity map imaging * of both the H-atoms (C-H bond cleavage) and the methyl radicals (C-C bond cleavage) have been We have excited jet-cooled pyrazine molecules into the S2(ππ ) state with 4.7-eV deep UV pulses measured. A full account of the most interesting results will be given at the Conference. and observed subsequent electronic dephasing processes by single photon ionization using 9.3-eV VUV pulses. As seen in Fig. 1, the photoelectron image dramatically changes with the pump-probe delay times. As * we previously demonstrated [5], S2(ππ ) undergoes

internal conversion to S1(n*) within 22 fs, while the * present study revealed that vibrationally-hot S1(nπ ) * further decays with 14.8 ps into S0 and T1(nπ ). * Additionally, configuration interaction of S2(ππ ) state was clearly observed via photoionization into multiple cationic states (Fig. 2).

* Fig. 2 (a) Photoelectron spectrum of S2( ). (b) Fig. 1 2D slices through the 3D photoelectron scattering distributions * Electronic configurations for S2( ) and cationic obtained at (a) 1, (b) 25, (c) 49, (d) 1000, (e) 10000, and (f) 80000 fs. states. References References [1] G. Balerdi, J. Woodhouse, A. Zanchet, R. de Nalda, M. L. Senent, A. García-Vela, L. Bañares, Phys. Chem. [1] T. Suzuki, Annu. Rev. Phys. Chem. 57, 555 (2006). Chem. Phys., 18, 110 (2016). [2] T. Horio, R. Spesyvtsev, and T. Suzuki, Opt. Express 21, 22423 (2013). [2] S. Marggi Poullain, D. V. Chicharro, A. Zanchet, M. G. González, L. Rubio-Lago, M. L. Senent, A. García- [3] T. Horio, R. Spesyvtsev, and T. Suzuki, Opt. Lett. 39, 6021 (2014). Vela, L. Bañares, Phys. Chem. Chem. Phys., 18, 17054 (2016). [4] T. Horio et al. J. Chem. Phys. 145, 044306 (2016). [3] Zanchet, L. Bañares, M. L. Senent, A. García-Vela, Phys. Chem. Chem. Phys., 18, 33195 (2016). [5] T. Horio, T. Fuji, Y.-I. Suzuki, and T. Suzuki, J. Am. Chem. Soc. 131, 10392 (2009).

42 4543 S-20

Reactions of atomic radicals with aliphatic and aromatic hydrocarbons by crossed beam experiments

Nadia Balucani

DCBB – Università degli Studi di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy [email protected]

In our laboratory, we have pursued a systematic investigation of bimolecular reactions involving atomic radicals and simple hydrocarbons (HCs) by means of the crossed molecular beam method with mass spectrometric detection (see, for instance, Ref. [1]). Advantage has been taken of an efficient, versatile radiofrequency discharge beam source for the production of atomic (C, N, O, S, Cl) and diatomic (CN, OH, C2) radicals [2].

In this contribution, recent results on the reactions involving either atomic oxygen in its ground electronic state, O(3P), or atomic nitrogen in its first electronically excited state, N(2D), and unsaturated HCs, as well as benzene, will be presented. The investigated systems are of relevance in combustion chemistry (O+HCs, [3]) or in the chemistry of the upper atmosphere of Titan, the giant moon of Saturn (N(2D)+HCs, [4]) with potential implications in prebiotic chemistry [5].

Acknowledgments: Support by Fondazione Cassa Risparmio Perugia (Project 2015.0331.021 Scientific and Technological Research), University of Perugia (Fondo Ricerca di Base 2014), and MIUR (PRIN 2015, STARS in the CAOS - Simulation Tools for Astrochemical Reactivity and Spectroscopy in the Cyberinfrastructure for Astrochemical Organic Species, 2015F59J3R) is gratefully acknowledged.

References [1] P. Casavecchia et al., Int. Rev. Phys. Chem., 34, 161 (2015); and references therein. [2] F. Leonori et al., Mol. Phys., 108, 1097 (2010). [3] N. Balucani et al., Energy, 43, 47 (2012). [4] V. Vuitton, O. Dutuit, M. A. Smith, N. Balucani, Chemistry of Titan's atmosphere, in: Titan: Surface, Atmosphere and Magnetosphere (ISBN-10: 0521199921), I. Mueller-Wodarg, C. Griffith, E. Lellouch & T. Cravens, Eds., Cambridge University Press, 2014. [5] N. Balucani, Chem. Soc. Rev., 41, 5473 (2012); and refs. therein

4644 S-21

Reactions of atomic radicals with aliphatic and aromatic Real-space imaging of OH radicals scattered from liquid hydrocarbons by crossed beam experiments surfaces

Nadia Balucani Robert H. Bianchini, Maria A. Tesa-Serrate, Matthew L. Costen and Kenneth G. McKendrick DCBB – Università degli Studi di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy [email protected] Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK In our laboratory, we have pursued a systematic investigation of bimolecular reactions involving atomic radicals and simple hydrocarbons (HCs) by means of the crossed molecular beam method with The mechanisms of radical reactions at liquid surfaces remain relatively much less well explored than mass spectrometric detection (see, for instance, Ref. [1]). Advantage has been taken of an efficient, the corresponding reactions in the gas-phase or at solid surfaces. The OH radical is a ubiquitous versatile radiofrequency discharge beam source for the production of atomic (C, N, O, S, Cl) and species that is involved in gas-liquid interfacial processes of practical interest in a number of diatomic (CN, OH, C2) radicals [2]. environments, most notably at aerosol surfaces in the atmosphere. The ‘ageing’ of the aerosol through oxidation reactions initiated by OH is a key process affecting its capacity to grow by absorbing further In this contribution, recent results on the reactions involving either atomic oxygen in its ground water molecules, with important climatic consequences through the effect on radiative balance and 3 2 electronic state, O( P), or atomic nitrogen in its first electronically excited state, N( D), and cloud condensation. unsaturated HCs, as well as benzene, will be presented. The investigated systems are of relevance in combustion chemistry (O+HCs, [3]) or in the chemistry of the upper atmosphere of Titan, the giant 2 We have previously developed and exploited a method to study the primary elementary step in the moon of Saturn (N( D)+HCs, [4]) with potential implications in prebiotic chemistry [5]. reactions of OH with selected model liquid surfaces chosen as proxies to represent the range of chemical functionalities present at atmospheric aerosol surfaces[1-3]. Those experiments were based Acknowledgments: Support by Fondazione Cassa Risparmio Perugia (Project 2015.0331.021 Scientific and on production of OH by photolysis of a suitable precursor above the surface of the liquid. While Technological Research), University of Perugia (Fondo Ricerca di Base 2014), and MIUR (PRIN 2015, STARS in the CAOS - Simulation Tools for Astrochemical Reactivity and Spectroscopy in the Cyberinfrastructure for providing valuable new insight, they did not allow ready control of the incident translational and Astrochemical Organic Species, 2015F59J3R) is gratefully acknowledged. internal energies of the OH projectile, which are dictated by the choice of precursor and photolysis wavelength. We have now overcome this limitation by introducing a pulsed molecular-beam source of OH (or, for technical reasons, OD); this allows the translational energy to be tuned through the choice of carrier gas, accompanied by rotational cooling into the lowest few states. The OD is detected by laser-induced fluorescence (LIF) excited by a probe beam propagating a fixed distance above the surface. The incident and scattered OD is resolved in time and distinguished by very different in and out-going rotational distributions. The scattered intensities from an inert reference liquid (perfluoropolyether) may be compared with those from potentially reactive model liquids such as the long-chain, branched hydrocarbon, squalane (C30H62, 2,6,10,15,19,23-hexamethyltetracosane) and its partially unsaturated analogue, squalene. This allows the survival probability (or its complement, the uptake coefficient) to be determined for different liquids. The contrasting translational energy dependencies of the survival probabilities can be interpreted in terms of distinct reaction mechanisms at saturated and unsaturated sites.

Most recently, we have extended these experiments further by introducing an imaging detection scheme. The probe beam is expanded into a sheet and the LIF emission is imaged, providing a real- space measurement of the spatial distribution of OH (or OD). By varying the delay between the pulsed-discharge source and the probe laser pulse, we are able to measure product OD state-selective speed and angular distributions and their dependence on incident angle. This additional information will enhance our ability to diagnose different scattering mechanisms through the distinct dynamical signatures of OD that survives collisions with the liquid surface.

References [1] P. Casavecchia et al., Int. Rev. Phys. Chem., 34, 161 (2015); and references therein. [2] F. Leonori et al., Mol. Phys., 108, 1097 (2010). References [3] N. Balucani et al., Energy, 43, 47 (2012). [1] P. A. J. Bagot, C. Waring, M. L. Costen and K. G. McKendrick, J. Phys. Chem. C, 112, 10868(2008). [4] V. Vuitton, O. Dutuit, M. A. Smith, N. Balucani, Chemistry of Titan's atmosphere, in: Titan: Surface, [2] C. Waring, K. L. King, P. A. J. Bagot, M. L. Costen and K. G. McKendrick, Phys. Chem. Chem. Phys., 13, Atmosphere and Magnetosphere (ISBN-10: 0521199921), I. Mueller-Wodarg, C. Griffith, E. Lellouch & 8457(2011). T. Cravens, Eds., Cambridge University Press, 2014. [3] K. L. King, G. Paterson, G. E. Rossi, M. Iljina, R. E. Westacott, M. L. Costen, and K. G. McKendrick, [5] N. Balucani, Chem. Soc. Rev., 41, 5473 (2012); and refs. therein Phys. Chem. Chem. Phys., 15, 12852(2013).

44 4745 H-10

Oscillation of branching ratios between the D(2s)+D(1s) and the D(2p)+D(1s) channels in direct photodissociation of D2

Yuxiang Mo, Jie Wang, and Qingnan Meng

Department of Physics, Tsinghua University Beijing, 100084, China

The photodissociation of H2 serves as a benchmark to test the theory of both the electronic structure calculation and the theory of dynamics. It was predicted in 1987 [1] that there is an oscillation of the branching ratios between the photofragment H(2s) and H(2p) near the threshold (14.682 eV) due to the interference of the dissociation continua. We observed this experimentally for the first time.

The experiment employed XUV laser pump and UV laser probe method. The XUV light was prepared by four-wave mixing of two laser beams. The D(2s) and D(2p) was detected by the one-photon ionization method and discriminated using the lifetime difference between H(2s) and H(2p). We have measured the branching ratios about 2000 cm-1 above the threshold of photodissociation. The anisotropy parameters describing the angular distribution of the fragments have also been measured.

The experimental results confirmed that the branching ratios have oscillation behavior that are approximately similar to those of the theoretical predictions, however, there are large difference, in particular in the threshold region. The oscillation can also be understood using a simple model in which the potential energy curves are replaced by rectangular potential wells, and the related parameters of the potential wells determined from fitting the experimentally measured branching ratios characterize the ab initio PECs reasonably.

The experimental results provide a very interesting example of wavefunction interference similar to those of two-slit interference in optics, however, with the effective widths of the potential wells as the slits.

References [1]J. A. Beswick and M.Glass-Maujean, Phys. Rev. A. 35, 8(1987).

4846 Oscillation of branching ratios between the D(2s)+D(1s) and the D(2p)+D(1s) channels in direct photodissociation of D2

Yuxiang Mo, Jie Wang, and Qingnan Meng Department of Physics, Tsinghua University Beijing, 100084, China The photodissociation of H2 serves as a benchmark to test the theory of both the electronic structure calculation and the theory of dynamics. It was predicted in 1987 [1] that there is an oscillation of the branching ratios between the photofragment H(2s) and H(2p) near the threshold (14.682 eV) due to the interference of the dissociation continua. We observed this experimentally for the first time.

The experiment employed XUV laser pump and UV laser probe method. The XUV light was prepared by four-wave mixing of two laser beams. The D(2s) and D(2p) was detected by the one-photon ionization method and discriminated using the lifetime difference between H(2s) and H(2p). We have measured the branching ratios about 2000 cm-1 above the threshold of photodissociation. The anisotropy parameters describing the angular distribution of the fragments have also been measured. Special Session on NO3 The experimental results confirmed that the branching ratios have oscillation behavior that are approximately similar to those of the theoretical predictions, however, there are large difference, in particular in the threshold region. The oscillation can also be understood using a simple model in (In Order of Presentation) which the potential energy curves are replaced by rectangular potential wells, and the related parameters of the potential wells determined from fitting the experimentally measured branching ratios characterize the ab initio PECs reasonably.

The experimental results provide a very interesting example of wavefunction interference similar to those of two-slit interference in optics, however, with the effective widths of the potential wells as the slits.

References [1]J. A. Beswick and M.Glass-Maujean, Phys. Rev. A. 35, 8(1987).

46 49 NO3, the Teller radical Introductory remarks to the mini- symposium on NO3

Takeshi Oka

Department of Chemistry and Department of Astronomy and Astrophysics The Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 USA

Just like Herzberg’s group in Ottawa dominated electronic spectroscopy of free radicals in the ultraviolet and visible from 1950 to 70s, Hirota’s group in Okazaki dominated microwave and infrared spectroscopy of free radicals from 1970 to 80s. Radicals with D3h symmetry like CH3 and NO3 are Hirota’s love. His milestone, the spectroscopy and kinetics of CH3, are beautifully summarized in his prefatory chapter in the 1991 Annual Review of Physical Chemistry [1]. This mini-symposium is on his second love, NO3. In 1928 Born and Oppenheimer separated the electronic, vibrational and rotational Hamiltonians and showed their energy ratio to be 1: κ2: κ4, with κ ~ 0.1, the Born-Oppenheimer constant. The task of studying their interactions fell to Edward Teller, then 20 years old. His formulation of the Coriolis interaction [2] and vibronic interactions [3,4] are classics. I call NO3 “the Teller radical” because both the vibration-rotation interaction and vibronic interaction appear in their most beautiful ways in this molecule and provide a battle ground for spectroscopists. The controversy on NO3 stemmed from the assignment of its ν3 vibrational mode in the ground electronic state. Ishiwata et al. [5] observed LIF and from difference frequencies assigned the -1 -1 - spectrum at 1480 cm to the ν3 band close to the ν3 band at 1390 cm of NO3 listed in Table 44 of Herzberg’s Volume II. Soon the direct infrared transition was observed and the band origin was located at 1492.3929(9) cm-1 [6]. Although some anomalies in detailed structure were noted, this looked like a natural and robust assignment of the ν3 band for over 20 years. -1 Then Stanton’s ab initio theory [7] threw in a bomb and located the ν3 band at ~ 1000 cm nearly -1 500 cm lower, very close to the ν1 band. This new value was supported by Jacox from her low temperature rare gas matrix studies using 15N and 18O isotopes [8] which assigned the band at 1492 -1 cm to the ν3 + ν4 band. But, then, where is ν3 !? Stanton argued that the intensity of the ν3 band is 700 times less than that of the ν3 + ν4 band [9]. I was surprised; such a near perfect destructive interference requires an incredible accident on energy levels and vibronic interaction. Anyhow the community of high resolution spectroscopy has since split into two factions ― Group -1 I who believe “Assignment I” by Hirota in which the 1492 cm spectrum is assigned to the ν3 band, and Group II who believe “Assignment II” by Kawaguchi in which the band is assigned to the ν3 + ν4 band. A great many papers on the analyses of vibration-rotation structure supporting the respective assignments have been published by Hirota’s group I summarized in [10] and Kawaguchi’s group II summarized in [11] but no consensus has been reached as of now. While the battles between Hirota and Kawaguchi have been in the area of the infrared spectrum of NO3 and vibration-rotation interactions, invited speakers of this mini-symposium talk more on electronic spectrum of NO3 and vibronic interactions. This will shed light to the controversy from an independent perspective.

References [1] E. Hirota, Ann. Rev. Phys. Chem. 42, 1 (1991) [2] E. Teller & L. Tisza, Z. Physik, 73, 791 (1932) [3] G. Herzberg & E. Teller, Z. Physik. Chem. B21, 410 (1933) [4] H. A. Jahn & E. Teller, Proc. Roy. Soc. 161A, 220 (1937) [5] T. Ishiwata, I. Fujiwara, Y. Naruge, K. Obi, & I. Tanaka, J. Phys. Chem. 87, 1349 (1983) [6] T. Ishiwata, I. Tanaka, K. Kawaguchi, & E. Hirota, J. Chem. Phys., 82, 2196 (1985) [7] J. F. Stanton, J. Chem. Phys. 126. 1343 (2007) [8] M. E. Jacox and W. E. Thompson, J. Chem. Phys. 129, 204306 (2008) [9] J. F. Stanton, Mol. Phys. 107, 1059 (2009) [10] E. Hirota, J. Mol. Spectrosc. 310. 99 (2015) [11] K. Kawaguchi, R. Fujimori, J. Tang, & T. Ishiwata, J. Mol. Spectrosc. 314, 73 (2015)

5048 N-01

NO3, the Teller radical Introductory remarks to the mini- Rotationally-Resolved High-Resolution Laser Spectroscopy of symposium on NO3 B-X transition of Nitrate Radical

Takeshi Oka a) b) a) c) d) S. Kasahara , K. Tada , M. Hirata , T. Ishiwata , and E. Hirota Department of Chemistry and Department of Astronomy and Astrophysics The Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 USA a)Molecular Photoscience Research Center, Kobe University, Kobe 657-8501, Japan b)Graduate School of Engineering, Kyoto University, Kyoto 615-8530, Japan Just like Herzberg’s group in Ottawa dominated electronic spectroscopy of free radicals in the c)Faculty of Information Sciences, Hiroshima City University, Hiroshima 731-3194, Japan ultraviolet and visible from 1950 to 70s, Hirota’s group in Okazaki dominated microwave and infrared d)The Graduate University for Advanced Studies, Kanagawa 240-0193, Japan spectroscopy of free radicals from 1970 to 80s. Radicals with D3h symmetry like CH3 and NO3 are Hirota’s love. His milestone, the spectroscopy and kinetics of CH3, are beautifully summarized in his The nitrate radical NO3 has been known as an important intermediate in chemical reaction in the night- prefatory chapter in the 1991 Annual Review of Physical Chemistry [1]. This mini-symposium is on 2 2 2 time atmosphere. The three lowest electronic states X A2’, A E’’, and B E’ are coupled by vibronic his second love, NO3. interaction, and therefore NO3 radical becomes one of the model molecule for understanding the Jahn- In 1928 Born and Oppenheimer separated the electronic, vibrational and rotational Hamiltonians 2 4 Teller (JT) and pseudo Jahn-Teller (PJT) effects. The optically allowed B-X transition has been and showed their energy ratio to be 1: κ : κ , with κ ~ 0.1, the Born-Oppenheimer constant. The task observed as a strong absorption and LIF excitation spectrum by several groups. The strongest of studying their interactions fell to Edward Teller, then 20 years old. His formulation of the Coriolis absorption line at 662 nm is called as 0-0 band of B-X transition which is used to detect the NO3 interaction [2] and vibronic interactions [3,4] are classics. I call NO3 “the Teller radical” because both radical in the atmosphere, however, the rotational assignment still remained because it is too the vibration-rotation interaction and vibronic interaction appear in their most beautiful ways in this complicated. [1] Recently, we reported the rotationally-resolved high-resolution spectrum and the molecule and provide a battle ground for spectroscopists. 14 15 Zeeman splittings of the B-X 0-0 band for NO3 [2, 3] and NO3 [4] by using sub-Doppler high- The controversy on NO3 stemmed from the assignment of its ν3 vibrational mode in the ground resolution spectroscopic technique. For NO3 radical, it is expected to observe large Zeeman electronic state. Ishiwata et al. [5] observed LIF and from difference frequencies assigned the -1 -1 - splitting even in the small magnetic field. The Zeeman splitting is very useful to assign the spectrum at 1480 cm to the ν3 band close to the ν3 band at 1390 cm of NO3 listed in Table 44 of observed rotational lines even in the strong perturbing region. We expanded the measurement of Herzberg’s Volume II. Soon the direct infrared transition was observed and the band origin was the transition to vibrationally excited state observed around 628 nm. located at 1492.3929(9) cm-1 [6]. Although some anomalies in detailed structure were noted, this looked like a natural and robust assignment of the ν3 band for over 20 years. -1 Then Stanton’s ab initio theory [7] threw in a bomb and located the ν3 band at ~ 1000 cm nearly NO3 was produced by a pyrolysis reaction of N2O5 at 300ºC (N2O5 → NO3 + NO2) with a heater -1 500 cm lower, very close to the ν1 band. This new value was supported by Jacox from her low attached to a pulsed nozzle, and collimated to a molecular beam with a skimmer and a slit. temperature rare gas matrix studies using 15N and 18O isotopes [8] which assigned the band at 1492 Rotationally- resolved high-resolution fluorescence excitation spectra were measured by crossing a -1 cm to the ν3 + ν4 band. But, then, where is ν3 !? Stanton argued that the intensity of the ν3 band is single-mode laser beam perpendicular to a collimated NO3 beam. The typical linewidth was 30 MHz -1 700 times less than that of the ν3 + ν4 band [9]. I was surprised; such a near perfect destructive and the absolute wavenumber was calibrated with accuracy 0.0001 cm by measurement of the interference requires an incredible accident on energy levels and vibronic interaction. Doppler-free saturation spectrum of iodine molecule and fringe pattern of the stabilized etalon. Anyhow the community of high resolution spectroscopy has since split into two factions ― Group -1 I who believe “Assignment I” by Hirota in which the 1492 cm spectrum is assigned to the ν3 band, The observed rotational lines were too complicated to find any rotational series. In the observed 2 and Group II who believe “Assignment II” by Kawaguchi in which the band is assigned to the ν3 + ν4 spectra, mainly the rotational line pairs from the X A2’(υ''=0, K''=0, N''=1, F1 and F2 levels) are 2 band. A great many papers on the analyses of vibration-rotation structure supporting the respective assigned unambiguously by using the combination differences of the X A2’ state and measurement assignments have been published by Hirota’s group I summarized in [10] and Kawaguchi’s group II of the Zeeman splittings. The observed results suggest the observed vibrationally excited states of the summarized in [11] but no consensus has been reached as of now. B 2E’ state are also interacts with the other vibronic levels similar to the B While the battles between Hirota and Kawaguchi have been in the area of the infrared spectrum 2 E’(υ'=0) level. of NO3 and vibration-rotation interactions, invited speakers of this mini-symposium talk more on electronic spectrum of NO3 and vibronic interactions. This will shed light to the controversy from an independent perspective.

References [1] E. Hirota, Ann. Rev. Phys. Chem. 42, 1 (1991) [2] E. Teller & L. Tisza, Z. Physik, 73, 791 (1932) [3] G. Herzberg & E. Teller, Z. Physik. Chem. B21, 410 (1933) [4] H. A. Jahn & E. Teller, Proc. Roy. Soc. 161A, 220 (1937) [5] T. Ishiwata, I. Fujiwara, Y. Naruge, K. Obi, & I. Tanaka, J. Phys. Chem. 87, 1349 (1983) References [6] T. Ishiwata, I. Tanaka, K. Kawaguchi, & E. Hirota, J. Chem. Phys., 82, 2196 (1985) [1] R. T. Carter, K. F. Schmidt, H. Bitto, and J. R. Huber, Chem. Phys. Lett. 257, 297 (1996). [7] J. F. Stanton, J. Chem. Phys. 126. 1343 (2007) [2] K. Tada, W. Kashihara, M. Baba, T. Ishiwata, E. Hirota, and S. Kasahara, J. Chem. Phys. 141, 184307 [8] M. E. Jacox and W. E. Thompson, J. Chem. Phys. 129, 204306 (2008) (2014). [9] J. F. Stanton, Mol. Phys. 107, 1059 (2009) [10] E. Hirota, J. Mol. Spectrosc. 310. 99 (2015) [3] K. Tada, T. Ishiwata, E. Hirota, and S. Kasahara, J. Mol. Spectrosc., 321, 23 (2016). [11] K. Kawaguchi, R. Fujimori, J. Tang, & T. Ishiwata, J. Mol. Spectrosc. 314, 73 (2015) [4] K. Tada, K. Teramoto, T. Ishiwata, E. Hirota, and S. Kasahara, J. Chem. Phys. 142, 114302 (2015).

48 5149 N-02

Cavity Ringdown Spectra of the a1ʹʹ and eʹ Vibronic bands of the Electronic Transition of Jet-cooled NO3 𝟐𝟐𝟐𝟐 ′′ 𝟐𝟐𝟐𝟐 ′ 𝐀𝐀𝐀𝐀̃ 𝐄𝐄𝐄𝐄 −𝐗𝐗𝐗𝐗̃ 𝐀𝐀𝐀𝐀𝟐𝟐𝟐𝟐 Terry A. Miller

Department of Chemistry and Biochemistry, The Ohio State University, Columbus Ohio 43210 USA

The magnitude of the Jahn-Teller (JT) effect in the degenerate electronic states of NO3 has been the subject of considerable research in our group and others. This talk will present our studies of the rotational structure involving A-state a1ʹʹ and eʹ vibronic levels and the X-state a2ʹ vibronic level (vibrationless) in the A E A electronic transition. The experimental work was carried out using ̃ ̃ 1 cavity ringdown spectroscopy2 ′′ 2in ′the near IR and a jet-cooled NO3 sample. Hirota and co-workers ̃ 2 1 previously reported rotational−X̃ structure for the 40 band and rotational contours of several bands were 2 reported by Deev, et. al. Both of these experiments involved room temperature NO3.

Our group has collected high-resolution rotationally resolved spectra for a number of bands at a 1 rotational temperature of ≈ 25K. We have observed and nearly completed the analysis of the 30 and 1 1 1 30 40 parallel bands ending in A states of a1ʹʹ vibronic symmetry as well as re-examining the 40 band. 1 2 Preliminary analyses of the perpendicular 2 and 20 40 bands to eʹ vibronic levels of the A state are ̃ in hand. We will discuss the implications Iof the rotational analysis for the JT effect and related 0 ̃ characterization of the A E state of NO3. 2 ′′ ̃

References [1] E. Hirota, K. Kawaguchi, M. Fujitake, N. Ohashi, and I. Tanaka, J. Chem. Phys. 107, 2829 (1997) [2] A. Deer, J. Sommar and M. Okumura, J. Chem. Phys. 122, 224305 (2005)

5250 N-03

Cavity Ringdown Spectra of the a1ʹʹ and eʹ Vibronic bands of the Quantum dynamics and potential energy surfaces of NO3 Electronic Transition of Jet-cooled NO3 Wolfgang Eisfeld a) and Alexandra Vielb) 𝟐𝟐𝟐𝟐 ′′ 𝟐𝟐𝟐𝟐 ′ 𝐀𝐀𝐀𝐀̃ 𝐄𝐄𝐄𝐄 −𝐗𝐗𝐗𝐗̃ 𝐀𝐀𝐀𝐀𝟐𝟐𝟐𝟐 Terry A. Miller a)Theoretical Chemistry, Bielefeld University, Postfach 100131, Bielefeld, Germany b)Institut de Physique de Rennes, CNRS and Univerité de Rennes 1, UMR 6251, Rennes, France Department of Chemistry and Biochemistry, The Ohio State University, Columbus Ohio 43210 USA The complex spectroscopy and photochemistry of the nitrate radical provides a wide range of unusual

The magnitude of the Jahn-Teller (JT) effect in the degenerate electronic states of NO3 has been the phenomena of which several are at most partially understood. Both experiment and theory are facing subject of considerable research in our group and others. This talk will present our studies of the numerous obstacles in answering the open questions. Over the past years we have been developing the methodology to attack several of these issues by theory and will report our latest results. rotational structure involving A-state a1ʹʹ and eʹ vibronic levels and the X-state a2ʹ vibronic level (vibrationless) in the A E A electronic transition. The experimental work was carried out using ̃ ̃ 1 cavity ringdown spectroscopy2 ′′ 2in ′the near IR and a jet-cooled NO3 sample. Hirota and co-workers The key was the development of accurate diabatic potential energy surface (PES) models based on ̃ 2 1 previously reported rotational−X̃ structure for the 40 band and rotational contours of several bands were high-level ab initio calculations[1] since simple[2] and even extended[3] vibronic coupling models 2 2 3 reported by Deev, et. al. Both of these experiments involved room temperature NO3. are insufficient in the case of the NO excited states. The finally obtained PES model for the E'' excited state allowed us to study the complex quantum dynamics in this interesting Jahn-Teller (JT) Our group has collected high-resolution rotationally resolved spectra for a number of bands at a active electronic state in detail. The well-known photodetachment spectrum can be explained 1 rotational temperature of ≈ 25K. We have observed and nearly completed the analysis of the 30 and satisfactorily for the first time based on first principle calculations.[1] It turns out that the JT coupling 1 1 1 is not strong enough to wash out a resolved spectrum entirely. On the other hand, the JT coupling is 30 40 parallel bands ending in A states of a1ʹʹ vibronic symmetry as well as re-examining the 40 band. 1 2 strong enough to lead to a strongly perturbed and extremely complex spectrum. We can explain the Preliminary analyses of the perpendicular 2 and 20 40 bands to eʹ vibronic levels of the A state are ̃ detachment spectrum as well as available direct absorption spectra (by CRDS) based on the in hand. We will discuss the implications Iof the rotational analysis for the JT effect and related 0 ̃ computation and analysis of the vibronic eigenstates in this electronic manifold.[4] The eigenstates characterization of the A E state of NO3. are determined by the triple-well topography of the lower adiabatic PES sheet and the corresponding 2 ′′ ̃ tunneling and geometric phase effects.

The present methodology is continuously developed further and is currently extended to include the 2 2 A2' ground state and the E' second excited state. Both states also show interesting quantum dynamics phenomena which can be explained by our theoretical studies.

References [1] W. Eisfeld, O. Vieuxmaire, and A. Viel, J. Chem. Phys., 140, 224109 (2014). References [2] S. Mahapatra, W. Eisfeld, and H. Köppel, Chem. Phys. Lett., 441, 7 (2007). [1] E. Hirota, K. Kawaguchi, M. Fujitake, N. Ohashi, and I. Tanaka, J. Chem. Phys. 107, 2829 (1997) [3] S. Faraji, H. Köppel, W. Eisfeld, and S. Mahapatra, Chem. Phys., 347, 110 (2008). [2] A. Deer, J. Sommar and M. Okumura, J. Chem. Phys. 122, 224305 (2005) [4] W. Eisfeld and A. Viel, J. Chem. Phys., 146, 034303 (2017).

50 5351 N-04

Assignment of the PE spectrum of NO3 anion revisited

Koichi Yamadaa) and Stephen C Rossb)

a)AIST, Onogawa 16-1, Tsukuba, 305-8569, Japan b)University of New Brunswick, Fredericton, NB, E3B 5A3, Canada

In 1991 Weaver et al. used photoelectron (PE) spectroscopy of the X ground electronic state of the NO3- ion to probe the vibrational levels of the higher lying X ground state and the A first excited ̃ electronic states of the NO3 radical [1]. Their original assignment involved symmetry forbidden ̃ transitions; the ν4 (degenerate-bending mode of symmetry e') sequences̃ contain forbidden transitions of Δv4 = odd. To explain these the authors invoked the possibility of very large vibronic interaction between the X and B states of the NO3 radical. ̃ ̃ The invocation of extremely large vibronic mixing of the X ground state of the NO3 radical leads to a prediction of a large shift of the frequency for the other e'-symmetry mode ν3 (degenerate-stretching) in 2007 by Stanton [2], from its previously assigned experimental̃ value as pointed out by Hirota [3].

Here we propose a possible alternative assignment of the same PE spectrum, one which does not involve any forbidden transitions. If correct this alternative assignment would not require the existence of a very large vibronic interaction, and as a consequence we conclude that the very low vibrational frequency for ν3 predicted by Stanton [2] may be unreliable. The revised assignments removes the weakest link of Hirota's argument [3].

References [1] Weaver, A.; Arnold, D.W.; Bradforth, S.E.; Neumark, D.M. J. Chem. Phys. 94, 1740-1750 (1991). [2] J.F. Stanton, J. Chem. Phys. 126, 134309-1-134309-20 (2007). [3]Hirota, E. J. Mol. Spectrosc. 310, 99- 104 (2015).

5452 N-05

Assignment of the PE spectrum of NO3 anion revisited SVL DF and 2C-R4WM spectroscopies of NO3

Koichi Yamadaa) and Stephen C Rossb) Masaru Fukushima and Takashi Ishiwata a)AIST, Onogawa 16-1, Tsukuba, 305-8569, Japan b)University of New Brunswick, Fredericton, NB, E3B 5A3, Canada Faculty of Information Sciences, Hiroshima City University, Hiroshima 731-3194, Japan

We have generated NO3 in supersonic free jet expansions and observed the laser induced fluorescence In 1991 Weaver et al. used photoelectron (PE) spectroscopy of the X ground electronic state of the (LIF) and two-color resonant four-wave mixing (2C-R4WM) signals of the electronic NO3- ion to probe the vibrational levels of the higher lying X ground state and the A first excited ̃ transition. We have measured dispersed fluorescence (DF) spectra from the 2single′ vibronic2 ′ levels electronic states of the NO3 radical [1]. Their original assignment involved symmetry forbidden 14 15 ̃ ̃ 2 ̃ (SVLs) of the state of NO3 and NO3 [1]. A noticeable feature of both spectra𝐵𝐵𝐵𝐵 𝐸𝐸𝐸𝐸 −𝑋𝑋𝑋𝑋from 𝐴𝐴𝐴𝐴the vibration- transitions; the ν4 (degenerate-bending mode of symmetry e') sequences̃ contain forbidden transitions less level is the appearance of ν4 progressions (ν4 is a degenerate bending vibrational mode); in the of Δv4 = odd. To explain these the authors invoked the possibility of very large vibronic interaction 0 0 0 spectra, the progressions,𝐵𝐵𝐵𝐵̃ 4 n, n = 0, 1, 2, 3, and 1 14 n, n = 0, 1, 2, exhibit decreasing intensities with between the X and B states of the NO3 radical. increasing the quantum number. Restricting the progressions only in the DF spectra, the intensity ̃ ̃ behavior of the ν4 progressions can be interpreted according to a discussion by Herzberg [2]. However The invocation of extremely large vibronic mixing of the X ground state of the NO3 radical leads to a this interpretation cannot be accepted, because the ν4 progression is also observed in a photo-electron prediction of a large shift of the frequency for the other e'-symmetry mode ν3 (degenerate-stretching) (PE) spectrum [3], which is an electronic transition between nondegenerate electronic states, i.e., that in 2007 by Stanton [2], from its previously assigned experimental̃ value as pointed out by Hirota [3]. from the state of the anion to the state of the radical with a PE, and thus vibronic coupling cannot be expected1 ′ in both states. This is2 one′ of the focusing points on this paper. In addition to this Here we propose a possible alternative assignment of the same PE spectrum, one which does not ̃ 1 ̃ 2 noticeable𝑋𝑋𝑋𝑋 feature𝐴𝐴𝐴𝐴 for the ν4 progression,𝑋𝑋𝑋𝑋 it𝐴𝐴𝐴𝐴 is found on the DF spectra that a vibrational level lies near involve any forbidden transitions. If correct this alternative assignment would not require the -1 the ν1 fundamental, 1050 cm . In consideration of results from infra-red absorption spectroscopy [4] existence of a very large vibronic interaction, and as a consequence we conclude that the very low and computational studies [5], it is concluded that the new level is an 1′ level, and is assigned to 3ν4. vibrational frequency for ν3 predicted by Stanton [2] may be unreliable. The revised assignments -1 The other 3ν4 levels with 2′ and ′symmetries have been assigned to ones at 1216 and 1176 cm , removes the weakest link of Hirota's argument [3]. -1 respectively, and the splitting between the 1′ and 2′ levels is unexpectedly𝑎𝑎𝑎𝑎 large, ~160 cm . This is the second focusing point on𝑎𝑎𝑎𝑎 this paper.𝑒𝑒𝑒𝑒 To confirm the 1′ assignment for the new level, 2C-R4WM spectroscopy has been applied to the NO𝑎𝑎𝑎𝑎3 system.𝑎𝑎𝑎𝑎 Unfortunately we have only obtained the 2C- 14 R4WM spectrum for the , = 0.5 level of NO3,𝑎𝑎𝑎𝑎 and thus, only from the rotational structure of the 2C-R4WM spectrum,2 we′ cannot judge whether the final level is 1′ or ′. However, including 𝐵𝐵𝐵𝐵̃ 𝐸𝐸𝐸𝐸1/2 𝐽𝐽𝐽𝐽 information from the DF spectrum, we can conclude that it must be 1′. To understand the two focusing points above, we propose our interpretation here, and we would𝑎𝑎𝑎𝑎 like𝑒𝑒𝑒𝑒 to stress that ours can understand the both. Our interpretation is based on a new vibronic coupling𝑎𝑎𝑎𝑎 mechanism proposed by Hirota [6], which suggests degenerate vibrational modes induce electronic orbital angular momentum even in non-degenerate electronic states and (this is written as in [6]) should be conserved, where is the induced [5]. We interpret this to mean that degenerate vibrations are strongly coupled with electron motion,𝐾𝐾𝐾𝐾𝐾𝐾 and that 𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾 the vibronic wave-function𝐾𝐾𝐾𝐾̃ 𝐾𝐾 𝐾𝐾 cannot 𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾𝐾 be separated, | ; ; ≠ | | . When𝐾𝐾𝐾𝐾 we accept the vibronic𝐾𝐾𝐾𝐾 coupling in the X A state, the progressions are naturally interpreted, because all members of the progressions are vibronically2 ′ allowed. This is 2 effective not𝐾𝐾𝐾𝐾 only𝐾𝐾𝐾𝐾 𝐾𝐾𝐾𝐾𝑙𝑙 for𝐾𝐾𝐾𝐾𝑙𝑙 the𝐾𝐾𝐾𝐾𝑙𝑙 DF spectrum, but also PE. It is thought that̃ one reason for the strong coupling of the degenerate vibration and non-degenerate electron motion in the state is nature of the molecular orbital (MO) of the un-paired electron, i.e. under a simple picture of the MO structure, the MO, 1 2′, of the state is a non-bonding one and consists only of 2ps of three O atoms [8], and the contribution of the center N atom is negligible, as displayed in [9]. It is thus thought that, under the situation,𝑎𝑎𝑎𝑎 the MO easily follows the vibrational motion (motions of three O’s). References [1] M. Fukushima and T. Ishiwata, 68th International Symposium on Molecular Spectroscopy, paper WJ03. [2] G. Herzberg, MM III, D. Van Nostrand Company (Canada), LTD. (1967), p. 157. [3] A. Weaver, D. W. Arnold, S. E. Bradforth, and D. M. Neumark, J. Chem. Phys. 94, 1740 (1991). [4] K. Kawaguchi et al., J. Phys. Chem. A 117, 13732 (2013). [5] J. F. Stanton, J. Chem. Phys. 126, 134309 (2007) and 69th ISMS, paper MI16. References [6] E. Hirota, J. Mol. Spectrosco. 310, 99 (2015). [1] Weaver, A.; Arnold, D.W.; Bradforth, S.E.; Neumark, D.M. J. Chem. Phys. 94, 1740-1750 (1991). [7] e.g. H. B. Gray, Electrons and Chemical Bonding, W. A. Benjamin INC. (1965); Open Source Text [2] J.F. Stanton, J. Chem. Phys. 126, 134309-1-134309-20 (2007). [3]Hirota, E. J. Mol. Spectrosc. 310, 99- Books, https://archive.org/details/ost-chemistry-electrons_chemical_bonding (retrieved June 30, 2017). 104 (2015). [8] W. Eisfeld and K. Morokuma, J. Chem. Phys. 113, 5587 (2000).

52 5553 N-06

Vibronic Interactions in the NO3 ground electronic state

Eizi Hirota

The Graduate University for Advanced Studies: SOKENDAI

Four doubly-degenerate vibrational bands of the NO3 radical in the ground electronic state , where either ν3 or ν4 singly excited, exhibited spectra affected by spin-orbit interactions and led2 to′ 2 first-order Coriolis coupling constants differing much from the force-field calculated values. The𝑋𝑋𝑋𝑋̃ two𝐴𝐴𝐴𝐴 constants, spin-orbit and Coriolis coupling, run parallel, in both magnitude and sign, suggesting that the rotation of the unpaired electron about the symmetry axis of the radical is closely and tightly coupled with the azimuthal motion of the degenerate vibration. In fact, some molecular parameters determined even in the ground vibronic state, such as centrifugal distortion constants and inertial defect, are better reproduced by using the observed Coriolis coupling constants, rather than the force- field calculated values. These findings suggest that the sum of the vibrational ℓ and the electronic Λ angular momenta plays essential roles. The present study will examine this view of the coupling between the unpaired electron and the degenerate vibrational𝛬𝛬𝛬𝛬̃ = 𝑙𝑙𝑙𝑙 𝑙𝑙 𝛬𝛬𝛬𝛬 mode more in detail than in my previous treatment by extending the coupling mechanism to higher excited vibrational states, while taking into account only one doubly degenerate mode ν4: the in-plane O–N–O bending, for the sake of simplicity and clarity.

As in the previous study, the v4 = 1 state is most reasonably expressed by a superposition function: (10) (01) [C1 |v4=1, ℓ4=±1>|e, Λ=0> + C1 |v4=0, ℓ4=0>|e, Λ=±1>]. In fact, this formulation allowed us to understand the observed Coriolis and spin-orbit constants, at least semi-quantitatively. This approach may be applied to the overtone states v4 = 2, = ±2 as it is. It should, however, be pointed out that −1 the effective spin-orbit constant aeff derived is about 1 cm , much smaller than the value as large as 30 to 50 cm−1 in the excited state. This fact𝛬𝛬𝛬𝛬̃ is ascribed to the mismatch in symmetry: electronic (a2’) versus vibrational (e’). In sharp contrast with these lower states, the v4 = 3, = ±3 states will ̃ −1 be split by the spin-orbit𝐵𝐵𝐵𝐵 interaction cross term up to 6 ASO, namely of the order of 150 cm , in agreement with the observation. 𝛬𝛬𝛬𝛬̃

5654 Vibronic Interactions in the NO3 ground electronic state

Eizi Hirota

The Graduate University for Advanced Studies: SOKENDAI

Four doubly-degenerate vibrational bands of the NO3 radical in the ground electronic state , where either ν3 or ν4 singly excited, exhibited spectra affected by spin-orbit interactions and led2 to′ 2 first-order Coriolis coupling constants differing much from the force-field calculated values. The𝑋𝑋𝑋𝑋̃ two𝐴𝐴𝐴𝐴 constants, spin-orbit and Coriolis coupling, run parallel, in both magnitude and sign, suggesting that the rotation of the unpaired electron about the symmetry axis of the radical is closely and tightly coupled with the azimuthal motion of the degenerate vibration. In fact, some molecular parameters determined even in the ground vibronic state, such as centrifugal distortion constants and inertial defect, are better reproduced by using the observed Coriolis coupling constants, rather than the force- field calculated values. These findings suggest that the sum of the vibrational ℓ and the electronic Λ angular momenta plays essential roles. The present study will examine this view of the coupling between the unpaired electron and the degenerate vibrational𝛬𝛬𝛬𝛬̃ = 𝑙𝑙𝑙𝑙 𝑙𝑙 𝛬𝛬𝛬𝛬 mode more in detail than in my previous treatment by extending the coupling mechanism to higher excited vibrational states, Poster Session A while taking into account only one doubly degenerate mode ν4: the in-plane O–N–O bending, for the sake of simplicity and clarity. 28 August 19:30 – 22:30

As in the previous study, the v4 = 1 state is most reasonably expressed by a superposition function: (10) (01) [C1 |v4=1, ℓ4=±1>|e, Λ=0> + C1 |v4=0, ℓ4=0>|e, Λ=±1>]. In fact, this formulation allowed us to understand the observed Coriolis and spin-orbit constants, at least semi-quantitatively. This approach may be applied to the overtone states v4 = 2, = ±2 as it is. It should, however, be pointed out that −1 the effective spin-orbit constant aeff derived is about 1 cm , much smaller than the value as large as 30 to 50 cm−1 in the excited state. This fact𝛬𝛬𝛬𝛬̃ is ascribed to the mismatch in symmetry: electronic (a2’) versus vibrational (e’). In sharp contrast with these lower states, the v4 = 3, = ±3 states will ̃ −1 be split by the spin-orbit𝐵𝐵𝐵𝐵 interaction cross term up to 6 ASO, namely of the order of 150 cm , in agreement with the observation. 𝛬𝛬𝛬𝛬̃

54 5755 A01 Breaking through the false coincidence barrier: photoelectron photoion coincidence spectroscopy for the study of elusive free radicals D. L. Osborn, C. A. Taatjes, C. C. Hayden, B. Sztáray, K. Voronova, P. Hemberger, and A. Bodi

+ 3 A02* Blackbody radiation induced absorption dynamics from the E 0g ( P2) ion-pair state of I2 S. Hoshino, M. Araki, and K. Tsukiyama

A03 High resolution laser spectroscopy of the BiO radical for the detection of electron’s electric dipole moment S. Yamaguchi, Y. Suematsu, H. Tokugawa, and H. Kanamori

A04* Detection of reactive oxygen species in laundry applications A. Stanczak, A. Beeby, and S. Scialla

A05 FTMW spectroscopy of cis-OOSO M. Nakajima and Y. Endo

A06* Infrared spectroscopic study for proton transfer from the radical cation of pentane to water clusters T. Endo, Y. Matsuda, and A. Fujii

A07 A molecular line survey toward the nearby galaxies NGC 1068, NGC 253, and IC 342 in the 100 GHz region with the Nobeyama 45-m radiotelescope S. Takano, T. Nakajima, K. Kohno, N. Harada, and E. Herbst

A08* Impact of 2-methylbutanal photochemistry in the atmosphere A. Kharazmi, M. F. Shaw, M.J.T. Jordan, and S. H. Kable

A09 Ultrafast photoelectron spectroscopy of electron-core wave packet in Rydberg N2 by single-order laser high harmonics M. Fushitani, Y. Toida, F. Légaré, and Akiyoshi Hishikawa

A10* Photodissociation studies of alkyl peroxy radicals E. N. Sullivan, B. Nichols, and D. M. Neumark

A11 Molecular constants determination for F2P(S)NCS by Fourier transform microwave spectroscopy and quantum chemical calculation N. Kuze, S. Watanabe, Y. Kawashima, and X. Zeng

A12* New mass spectrometric methods for detecting over 24 halogenated species simultaneously at ambient pressure X. He, S. Iyer, P. Zhou, Q. Zha, L. Ahonen, C..Yan, N. Sarnela, Y. Wang, M. Passananti, W. Nie, M. Ehn, M. Kulmala, T. Jokinen, H. Junninen, M. Rissanen, and M. Sipilä

58 A01 Breaking through the false coincidence barrier: photoelectron photoion A13 Development of time- and angle-resolved photoelectron spectroscopy using coincidence spectroscopy for the study of elusive free radicals vacuum ultraviolet light source at 29.5 eV D. L. Osborn, C. A. Taatjes, C. C. Hayden, B. Sztáray, K. Voronova, P. Hemberger, and A. J. Nishitani, C. W. West, C. Higashimura, and T. Suzuki Bodi A14* Photochemical reaction of 2,3-dihydrofuran and its derivatives with infrared + 3 A02* Blackbody radiation induced absorption dynamics from the E 0g ( P2) free electron laser ion-pair state of I2 E. Yuda, M. Matsubara, F. Osada, Y. Negishi, K. Ito, W. Maruki, and K. Tsukiyama S. Hoshino, M. Araki, and K. Tsukiyama A15 Photochemical Production of H2 form aldehydes A03 High resolution laser spectroscopy of the BiO radical for the detection of A. Harrison, M. Shaw, A. Kharazmi, M. Jordan, and S. Kable electron’s electric dipole moment S. Yamaguchi, Y. Suematsu, H. Tokugawa, and H. Kanamori A16* Rydberg-Rydberg far infrared transition of NO K. Nishimura, S. Hoshino, and K. Tsukiyama A04* Detection of reactive oxygen species in laundry applications A. Stanczak, A. Beeby, and S. Scialla A17 Three-dimensional Potential energy surfaces of Rg-CO (Rg:He, Ne, Ar, Kr) K. Ohtsuki, T. Ishibashi, Y. Endo, and Y. Sumiyoshi A05 FTMW spectroscopy of cis-OOSO M. Nakajima and Y. Endo A18* Resolving non-adiabatic dynamics of hydrated electrons using ultrafast photoemission anisotropy A06* Infrared spectroscopic study for proton transfer from the radical cation of S. Karashima and T. Suzuki pentane to water clusters T. Endo, Y. Matsuda, and A. Fujii A19 Roles of biradical intermediates in the photochemical reaction of thiazole: matrix-isolation and theoretical study A07 A molecular line survey toward the nearby galaxies NGC 1068, NGC 253, J. Miyazaki, H. Takiyama, and M. Nakata and IC 342 in the 100 GHz region with the Nobeyama 45-m radiotelescope S. Takano, T. Nakajima, K. Kohno, N. Harada, and E. Herbst A20* Free radicals formed by H atom addition to dimethyl- and methoxyallene as determined by muon spin spectroscopy A08* Impact of 2-methylbutanal photochemistry in the atmosphere M. Scollon, I. McKenzie, L. Chandrasena, M. Mozafari, and P. Percival A. Kharazmi, M. F. Shaw, M.J.T. Jordan, and S. H. Kable A21 Chiral effects in collision induced dissociation of proton bound A09 Ultrafast photoelectron spectroscopy of electron-core wave packet in diastereomeric complexes of amino acids and 1-phenylethanol Rydberg N2 by single-order laser high harmonics M. Larsson, O. Rebrov, K. Kulyk, M. Ryding, R. D. Thomas, and E. Uggerud M. Fushitani, Y. Toida, F. Légaré, and Akiyoshi Hishikawa A22* 1+1' (VUV+UV) threshold ionization application in the study on dynamics of A10* Photodissociation studies of alkyl peroxy radicals reactive scattering E. N. Sullivan, B. Nichols, and D. M. Neumark W. Chen, D. Yuan, S. Yu, X. Yang, and X. Wang

A11 Molecular constants determination for F2P(S)NCS by Fourier transform A23 Probing the conformational behavior of the C4 alkyl-substituted Criegee microwave spectroscopy and quantum chemical calculation intermediates by FTMW spectroscopy N. Kuze, S. Watanabe, Y. Kawashima, and X. Zeng C. Cabezas, J.-C. Guillemin, and Y. Endo

A12* New mass spectrometric methods for detecting over 24 halogenated A24* Gas-phase autoxidation of cyclohexene as a direct source of organic highly species simultaneously at ambient pressure oxidized material X. He, S. Iyer, P. Zhou, Q. Zha, L. Ahonen, C..Yan, N. Sarnela, Y. Wang, M. Passananti, W. M. P. Rissanen, S. Iyer, X. He, M. Ehn, and T. Kurtén Nie, M. Ehn, M. Kulmala, T. Jokinen, H. Junninen, M. Rissanen, and M. Sipilä

59 A25 Quantitative temperature dependence of the microscopic hydration structures of hydrated phenol cations H. Ishikawa, I. Kurusu, R. Yagi, R. Kato, and Y. Kasahara

A26* Near-infrared spectroscopic study of interstellar free radicals S. Hamano, N. Kobayashi, H. Kawakita, and Keiichi Takenaka

+ A27 Laboratory detection of the linear carbon chain HC5N produced by top down chemistry M. Araki, A. Miyazaki, and K. Tsukiyama

A28 Atmospheric oxidation of NH3 by NO3 and OH radicals. Proton coupled electron transfer versus hydrogen atom transfer reaction mechanisms J. M. Anglada

A29 Far-infrared study of an interstellar molecule, HCOOCH3 by using synchrotron radiation K. Kobayashi, N. Ohashi, M. Fujitake, D. Tokaryk, and.B. E. Billinghurst

A30 Photo-induced dynamics of atmospherically important Criegee intermediates M. F. Vansco, H. Li, and M. I. Lester

A31 Comb-referenced sub-Doppler resolution spectroscopy of the 32 band of phosphine H. Sasada and S. Okuda

A32 Combustion reactions followed by photoelectron photoion coincidence spectroscopy: CRF-PEPICO B. Sztáray, K. Voronova, P. Hemberger, A. Bodi, and D. L. Osborn

A33 Lifetime measurements of bound metastable states in atomic negative anions in DESIREE R. D. Thomas, M. Kamińska, K. C. Chartkunchand, H. Hartman, O. M. Hole, R. F. Nascimento, M. Blom, M. Björkhage, A. Källberg, M. Larsson, P. Löfgren, P. Reinhed, S. Rosén, A. Simonsson, S. Mannervik, H. T. Schmidt, H. Cederquist, and D. Hanstorp

*Poster Award Candidates

60 A01

A25 Quantitative temperature dependence of the microscopic hydration Breaking Through the False Coincidence Barrier: Photoelectron structures of hydrated phenol cations Photoion Coincidence Spectroscopy for the Study of Elusive H. Ishikawa, I. Kurusu, R. Yagi, R. Kato, and Y. Kasahara Free Radicals

A26* Near-infrared spectroscopic study of interstellar free radicals David L. Osborn,a) Craig A. Taatjes,a) Carl C. Hayden,a) Bálint Sztáray,b) Krisztina S. Hamano, N. Kobayashi, H. Kawakita, and Keiichi Takenaka Voronova,b) Patrick Hemberger,c) and Andras Bodic)

+ A27 Laboratory detection of the linear carbon chain HC5N produced by top a)Combustion Research Facility, Sandia National Laboratories, Livermore, California, USA down chemistry b)Department of Chemistry, University of the Pacific, Stockton, California USA c) M. Araki, A. Miyazaki, and K. Tsukiyama Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute, Villigen, Switzerland

A28 Atmospheric oxidation of NH3 by NO3 and OH radicals. Proton coupled Photoelectron photoion coincidence (PEPICO) spectroscopy has a long history in the study of electron transfer versus hydrogen atom transfer reaction mechanisms thermodynamics and reaction dynamics of pure compounds. Recently it has emerged as a J. M. Anglada promising technique to obtain a comprehensive view of a chemical reaction that takes place on a potential energy surface with multiple deep wells. Such reactions have many possible reaction A29 Far-infrared study of an interstellar molecule, HCOOCH3 by using pathways, intermediates, and products. However, at the high ionization rates now possible with rd synchrotron radiation vacuum ultraviolet light from 3 generation synchrotrons, a new problem arises: false K. Kobayashi, N. Ohashi, M. Fujitake, D. Tokaryk, and.B. E. Billinghurst coincidences (the correlation of an electron from one neutral with an ion that arose from a different neutral) limit dynamic range to ~103. This limitation is severe when the goal is to observe rare

reaction intermediates (often free radicals) that are present in low concentrations. Both Criegee A30 Photo-induced dynamics of atmospherically important Criegee intermediates [1] and hydroperoxyalkyl radicals [2] are examples of elusive reaction intermediates intermediates whose observation required high dynamic range, and whose characterization has led to new M. F. Vansco, H. Li, and M. I. Lester understanding of their fundamental chemistry. We have devised a new method of periodic ion deflection, coupled with velocity map imaging of cations, to eliminate almost all false coincidences A31 Comb-referenced sub-Doppler resolution spectroscopy of the 32 band of in PEPICO spectroscopy. This presentation will demonstrate the technique, the improvement in phosphine dynamic range, and will foreshadow the new science that could be done with this technique. [3] H. Sasada and S. Okuda

A32 Combustion reactions followed by photoelectron photoion coincidence References spectroscopy: CRF-PEPICO B. Sztáray, K. Voronova, P. Hemberger, A. Bodi, and D. L. Osborn [1] C. A. Taatjes, O. Welz, A. J. Eskola, J. D. Savee, A. M. Scheer, D. E. Shallcross, B. Rotavera, E. P. F. Lee, J. M. Dyke, D. K. W. Mol, D. L. Osborn, and C. J. Percival, Science 340, 177, (2013) [2] J. D. Savee, E. Papajak, B. Rotavera, H. Huang, A. J. Eskola, O. Welz, L. Sheps, C. A. Taatjes, J. Zador, and A33 Lifetime measurements of bound metastable states in atomic negative D. L. Osborn, Science 347, 643, (2015) anions in DESIREE [3] B. Sztáray, K. Voronova, K. G. Torma, K. J. Covert, A. Bodi, P. Hemberger, T. Gerber, and D. L. Osborn, J. R. D. Thomas, M. Kamińska, K. C. Chartkunchand, H. Hartman, O. M. Hole, R. F. Chem. Phys. 147, 013944 (2017). Nascimento, M. Blom, M. Björkhage, A. Källberg, M. Larsson, P. Löfgren, P. Reinhed, S. Rosén, A. Simonsson, S. Mannervik, H. T. Schmidt, H. Cederquist, and D. Hanstorp

*Poster Award Candidates

6159 A02

Blackbody radiation induced absorption dynamics from + 3 the E 0g ( P2) ion-pair state of I2

Shoma Hoshino,a) Mitsunori Araki,b) and Koichi Tsukiyamab)

a)Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan b)Tokyo University of Science, 1-3 Kagurazaka, Shinjyuku-ku, Tokyo 162-8601, Japan

– 1 + Molecular iodine has a series of excited states correlating with the atomic ion pairs I ( S0) + I 3 1 1 ( P2,1,0, D2, and S0) for dissociation limits. Enormous efforts have been paid for understanding electronic structures in connection with development of laser excitation techniques, and a great volume of spectroscopic data has been published. Under those circumstances, renewed interest has

arisen for these excited states of I2 in view of providing benchmarks for study of their relaxation dynamics.[1] In this work, we investigated the decay dynamics from the highly excited vibrational + 3 levels of the E 0g ( P2) ion-pair state of I2.

+ 3 During the E 0g ( P2) (υE = 77) state was + 3 (b) Excitation: E 0g ( P2) vE = 77 Observed excited by two step laser excitation, the strong D 0 + (3P ) v = 85 (Ratio: 0.65) u 2 D + 3 + 3 UV fluorescence from the D 0u ( P2) (υD = 85, D 0u ( P2) vD = 86 (Ratio: 0.35) 86) states, which lie in the slightly higher

energy-level region from the laser excited state, was observed (Fig. 1, upper trace). This proves the upward population transfer from Emission intensity (arb. (arb. units) Emission intensity + 3 + 3 the E 0g ( P2) state to the D 0u ( P2) state. 210 220 230 240 250 260 + Wavelength (nm) The vibrational distribution in the D 0u + 3 1 + 3 Fig. 1. Dispersed D 0u ( P2) → X Σg UV fluorescence ( P2) state can be derived by the + 3 spectrum obtained by the excitation of the E 0g ( P2) Franck-Condon simulation of the intensity + 3 1 + (υE = 77) state. contour of the D 0u ( P2) → X Σg fluorescence band. The overall spectral pattern is reproduced very well by the simulation assuming

the relative populations of 0.65 : 0.35 for υD = 85 : 86, as illustrated in Fig. 1 (lower trace). By measurements of temporal profiles of the UV fluorescence and temperature dependence of + 3 + 3 the emission intensity, we presumed that the E 0g ( P2) → D 0u ( P2) upward transition is caused by absorption of blackbody radiation at room temperature. + 3 In this presentation, we will also discuss the cascade transition from the D 0u ( P2) ion-pair state following the absorption of blackbody radiation.

【Reference】 [1] For example, Hoshino et al., Phys. Chem. Chem. Phys., 18, 14292 (2016)

10262 A03

Blackbody radiation induced absorption dynamics from High Resolution Laser Spectroscopy of the BiO radical for + 3 the E 0g ( P2) ion-pair state of I2 the Detection of Electron’s Electric Dipole Moment

Shoma Hoshino,a) Mitsunori Araki,b) and Koichi Tsukiyamab) S. Yamaguchi, Y. Suematsu, and H. Tokugawa, and H. Kanamori a)Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan Tokyo Institute of Technology, Department of Physics. b)Tokyo University of Science, 1-3 Kagurazaka, Shinjyuku-ku, Tokyo 162-8601, Japan Recently, searching for the electron’s electric dipole moment (eEDM) using the metastable state – 1 + 232 3 −29 Molecular iodine has a series of excited states correlating with the atomic ion pairs I ( S0) + I of ThO (H 1) broke the lowest limit with the value of 8.7 × 10 e·cm [1]. However, its natural 3 1 1 lifetime would limit the accuracy of the measurement by uncertainty principal. Therefore, molecular ( P2,1,0, D2, and S0) for dissociation limits. Enormous efforts have been paid for understanding systems using the electronic ground state are desired for further progress in the eEDM detection. 209 2 electronic structures in connection with development of laser excitation techniques, and a great The BiO radical (X1 1/2) is such a candidate molecule for the measurement of eEDM because 2 its internal effective electric field was predicted to be stronger than ThO. Moreover, the 1/2 volume of spectroscopic data has been published. Under those circumstances, renewed interest has electronic ground state has an advantage for preparing large population at the lowest ground state arisen for these excited states of I2 in view of providing benchmarks for study of their relaxation which has a long lifetime, and is less magnetically sensitive and easy to align the molecular axis toward an external electric field. In the eEDM measurement, more than one electronic transitions dynamics.[1] In this work, we investigated the decay dynamics from the highly excited vibrational using lasers are indispensable for the manipulation and detection of a certain single quantum state. + 3 Therefore, we need information about the energy levels including hyperfine structures in both the levels of the E 0g ( P2) ion-pair state of I2. ground and excited electronic states. However, the hyperfine structure of BiO in the excited states + 3 During the E 0g ( P2) (υE = 77) state was has not been reported yet. Our purpose is to study the hyperfine structure in the electronic transition, Excitation: E 0 + (3P ) v = 77 (b) g 2 E and to confine the most appropriate transition for searching eEDM experiment in molecular beam Observed excited by two step laser excitation, the strong D 0 + (3P ) v = 85 (Ratio: 0.65) condition. u 2 D + 3 + 3 UV fluorescence from the D 0u ( P2) (υD = 85, At the first stage of this work, BiO was produced by the chemical reaction at room temperature. D 0u ( P2) vD = 86 (Ratio: 0.35) Bi + O2* ---> BiO + O, 86) states, which lie in the slightly higher in which Bi atom was vapored by heating the metal in a furnace at 1000 K and the excited oxygen

4 energy-level region from the laser excited was produced by discharging O2 in Ar buffer gas. The rovibronic transition of A2 1/2 (v=3) − X1 2 1/2 (v=0) was observed by diode laser absorption spectroscopy at the visible region. A 2 m long state, was observed (Fig. 1, upper trace). This White-type multi-pass cell and source modulation technique were used for high sensitive detection. proves the upward population transfer from In the result, we could observe many bundle of peaks which disappears immediately after stopping Emission intensity (arb. (arb. units) Emission intensity + 3 + 3 the discharge in the cell. Each rotational level splits into ten components by the hyperfine interaction the E 0g ( P2) state to the D 0u ( P2) state. 209 2 210 220 230 240 250 260 of Bi nuclear spin of I = 9/2. All those lines were analyzed by using an effective  Hamiltonian + Wavelength (nm) The vibrational distribution in the D 0u including magnetic dipole and electric quadrupole interaction as below. Fig. 1. Dispersed D 0+ (3P ) → X 1Σ+ UV fluorescence 3 u 2 g ( P2) state can be derived by the + 3 spectrum obtained by the excitation of the E 0g ( P2) Franck-Condon simulation of the intensity 1 � � � � The �hyperfine�� � ��� �constants� +�����+�� thus determined��� + �( Λare�� �very�� +Λ useful��� �for�) verifying+ ���(�� the� �� accuracy)���(2� of �relativistic 1) (υ = 77) state. + 3 1 + 2 E contour of the D 0u ( P2) → X Σg ab-initio calculation methods, which is inevitably necessary for determination of the absolute value fluorescence band. The overall spectral pattern is reproduced very well by the simulation assuming of eEDM from the observed Stark energy shift. This is because there are no experimental ways to know the enhanced factor on the electric field at the heavy nucleus position. For that purpose, the relative populations of 0.65 : 0.35 for υD = 85 : 86, as illustrated in Fig. 1 (lower trace). reproducibility check of the hyperfine constants is very useful since it contains relativistic effect of the unpaired electron at the nucleus position. By using these molecular constants, the spectrum at the By measurements of temporal profiles of the UV fluorescence and temperature dependence of low temperature in a typical supersonic jet condition was simulated, and the most appropriate single + 3 + 3 the emission intensity, we presumed that the E 0g ( P2) → D 0u ( P2) upward transition is caused by quantum state for the eEDM experiment is selected. In the next step, we tried to generate the BiO radical in molecular jet condition. For the beam absorption of blackbody radiation at room temperature. source, two reactions below using laser ablation were introduced. + 3 In this presentation, we will also discuss the cascade transition from the D 0 ( P ) ion-pair Bi(metal)* + O2/Ar buffer gas → BiO u 2 Bi2O3(solid)* + H2 buffer gas → BiO state following the absorption of blackbody radiation. By using a Q-mass spectrometer, a condition for gene rating BiO is optimized and the arrival time at the LIF detection point was measured. LIF detection of the nominated transition is now undergoing. 【Reference】 [1] For example, Hoshino et al., Phys. Chem. Chem. Phys., 18, 14292 (2016) [1] J. Baron, et al. Science 1248213 (2013)

102 63 61 A04

DETECTION OF REACTIVE OXYGEN SPECIES IN LAUNDRY APPLICATIONS

Anna Stanczaka), Andrew Beebya) and Stefano Sciallab)

a)Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom b)Brussels Innovation Centre, Procter&Gamble, Temselaan 100, 1853 Strombeek-Bever, Belgium

Bleaching agents are the key ingredient in laundry detergent and deliver a wide range of benefits such as: coloured stain removal, solution bleaching and malodour control. Laundry detergents rely on a longstanding combination of a hydrogen peroxide source and an amide or ester activator to generate organic peracid and hydrogen peroxide in situ. The challenge of this project was to develop a toolbox of molecular probes and spectroscopic techniques to enable qualitative and quantitative analysis of the key Reactive Oxygen Species (ROS) present in laundry applications. The toolbox will allow fundamental understanding of the bleaching process through the wash, which would enable the development of more efficient products.

Various kinds of UV-Vis and fluorescent probes were tested in model wash conditions, i.e. alkaline, aqueous environment. As a result a toolbox of three fluorescent probes was established for detection of ROS in laundry applications. Hydroxyl radicals can be analysed via the aromatic hydroxylation reaction with terephthalic acid, which results in generation of the fluorescent 2- hydroxyterephthalic acid. In alkaline conditions singlet oxygen can be signalling by bleaching of fluorescent 9,10-anthracenediyl-bis(methylene)dimalonic acid. Currently, existing spectroscopic probes for hydrogen peroxide or peracids are not specific for an individual peroxide, but for peroxides in general. In this work a new method, which allows distinction between hydrogen peroxide and peracid was developed. The new assay is based on the competitive kinetics between peroxides and 2- naphthylboronic acid and the reaction kinetics monitored by stopped flow.

6462 A05

DETECTION OF REACTIVE OXYGEN SPECIES IN LAUNDRY FTMW Spectroscopy of cis-OOSO APPLICATIONS  Masakazu Nakajimaa) and Yasuki Endob) Anna Stanczaka), Andrew Beebya) and Stefano Sciallab) a)Department of Basic Science, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan b)Department of Applied Chemistry, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, a)Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom Taiwan b)Brussels Innovation Centre, Procter&Gamble, Temselaan 100, 1853 Strombeek-Bever, Belgium

In general, potential energy surfaces of sulfur oxides SxOy have a relatively large number of local Bleaching agents are the key ingredient in laundry detergent and deliver a wide range of minima which correspond to structural isomers [1], reflecting the variety of oxidation states of benefits such as: coloured stain removal, solution bleaching and malodour control. Laundry detergents sulfur. Since most of SxOy isomers are polar transient species, pure rotational spectroscopy must be rely on a longstanding combination of a hydrogen peroxide source and an amide or ester activator to a useful tool to demonstrate their structural complexities. However, except for the diatomic generate organic peracid and hydrogen peroxide in situ. The challenge of this project was to develop molecule SO, only two such species, SSO [2] and cis-OSSO [3], have been observed through a toolbox of molecular probes and spectroscopic techniques to enable qualitative and quantitative microwave spectroscopy to date. analysis of the key Reactive Oxygen Species (ROS) present in laundry applications. The toolbox will In the present study, cis-OOSO, an isomer of sulfur trioxide SO3 (D3h), is spectroscopically allow fundamental understanding of the bleaching process through the wash, which would enable the characterized through pure rotational spectroscopy. This molecule has already been identified development of more efficient products. through IR spectroscopy as a photolysis product of SO3 in the Ar matrix [4]. Prior to the spectral survey, geometrical optimizations were carried out with the CCSD(T)-F12a/aug-cc-pVTZ level of Various kinds of UV-Vis and fluorescent probes were tested in model wash conditions, i.e. theory for several SO isomers reported in the previous DFT calculation [4]. On the singlet potential alkaline, aqueous environment. As a result a toolbox of three fluorescent probes was established for 3 surface, the most stable isomer is triangle SO3 (D3h), and the second lowest is the detection of ROS in laundry applications. Hydroxyl radicals can be analysed via the aromatic S-oxide-cyclic-SO isomer. The planar cis-OOSO isomer observed in this study is the third lowest, hydroxylation reaction with terephthalic acid, which results in generation of the fluorescent 2- 2 located at 8.6 kcal/mol lower energy than the lowest spin-allowed dissociation limit to triplet O2 and hydroxyterephthalic acid. In alkaline conditions singlet oxygen can be signalling by bleaching of triplet SO, while no stationary point for trans-form is found. By reference to the theoretical fluorescent 9,10-anthracenediyl-bis(methylene)dimalonic acid. Currently, existing spectroscopic ~ 1 probes for hydrogen peroxide or peracids are not specific for an individual peroxide, but for peroxides equilibrium structure of cis-OOSO ( X A' ), nine a-type and twelve b-type transitions of jet-cooled cis-OOSO were observed in a discharge plasma of an O2/SO2 gas mixture by Fourier-transform in general. In this work a new method, which allows distinction between hydrogen peroxide and 34 peracid was developed. The new assay is based on the competitive kinetics between peroxides and 2- microwave spectroscopy and MW-MW double-resonance spectroscopy. Those of the S naphthylboronic acid and the reaction kinetics monitored by stopped flow. isotopologue were also observed with its natural abundance. The rotational constants of cis-OOSO are experimentally determined to be A0 = 16421.456(3), B0 = 5536.878(3), and C0 = 4133.598(3) MHz. The calculated inertial defect shows a small positive value (+0.211 uÅ2), which is reasonable for a planar molecule.

References [1] for example, C. J. Marsden and B. J. Smith, Chem. Phys. 141, 335-353 (1990). [2] E. Tiemann, J. Hoeft, F. J. Lovas, and D. R. Johnson, The Journal of Chemical Physics, 60, 5000-5004 (1974). [3] F. J. Lovas, E. Tiemann, and D. R. Johnson, The Journal of Chemical Physics, 60, 5005-5010 (1974). [4] S.-H. Jou, M.-Y. Shen, C.-H. Yu, and Y.-P. Lee, The Journal of Chemical Physics, 104, 5745-5752 (1996).

62 6563 A06

Infrared spectroscopic study for proton transfer from the radical cation of pentane to water clusters

Tomoya Endo, Yoshiyuki Matsuda, and Asuka Fujii

Departement of Chemistry, Graduate School of Science, Tohoku Universiy, 6-3, Aramki-Aoba, Aoba-ku, Sendai, Japan

High proton donor abilities of cationic OH and NH have widely been demonstarted by spectroscopic investigations of gas phase clusters. Recently, we have clarified the extremely- high proton donor abilities of CH bonds in the radical cations of amines, ethers, and alcohols, although neutral CH is normally regarded as aprotic because of their low proton donor abilities.[1-3] The mechanisms for the enhancement of the proton donor abilities of their cationic CHs are rationalized by the hyperconjugation between CH and the nonbonding orbital which is a singly occupied molecular orbital (SOMO). Very + recently, we have reported the infrared (IR) signatures which Fig. 1 (a) Observed IR spectrum of [pentane-(H2O)1] indicate the high proton donor abilities of CH in cationic (b) Simulated vibrational spectrum for the most pentane, hexane, and pentane, although they do not have stable structure ατωB97X-D/6-311++G(3df,3pd) nonbonding orbitals.[4] In the present study, we carried out IR level. The simulated frequencies are scaled by 0.945 + spectroscopy of [pentane-(H2O)n] (n=1-3) to examine the proton donor ability of the pentane cation by probing the interaction between its CH bonds and the water clusters. Figs. 1 (a) and (b) are the observed IR spectrum of + [pentane-H2O] and the simulated spectrum of its most stable structure inserted in the figure. In this structure, the proton of cationic pentane is shared between the pentyl radical (C5H11) and the water molecule. The simulated spectrum agrees with the observed one. The observed and simulated free OH (ν1 and ν3) frequencies indicate the water molecule has the hydronium ion character, though the proton is not completely transferred. Figs. 2 (a) and (b) show the observed IR spectrum of + Fig.2 (a) Observed IR spectrum of [pentane- [pentane-(H2O)2] and the simulated spectrum of its most (H2O)2] (b) Simulated spectrum for the most stable stable structure. In the observed IR spectrum, a broad feature structure at ωB97X-D/6-311++G(3df,3pd) level. -1 appears in the frequency region lower than 2800 cm . This The simulated frequencies are scaled by 0.945 broad feature can be explained by the vibration of the proton which is transferred from the pentane cation to the water + moiety. Hence, we have concluded that [pentane-(H2O)2] forms the protontransferred structure. Figs. 3 (a) and (b) show the observed IR spectrum of + [pentane-(H2O)3] and the simulated spectrum of the most stable proton-transferred structure. In the observed spectrum, an intense broad band is observed in addition to the νCH, ν1, and ν3 bands. This broad band is attributed to the modes involving the vibration of the transferred proton. The proton transfer from CH of the pentane cation to the water clusters occurs at n≥2. Since the phenol cation requests at least three water molecules for the proton transfer, the Fig.3 (a) Observed IR spectrum of [pentane- + present results demonstrate that the proton donor ability of CH (H2O)3] (b) Simulated spectrum for the most stable in cationic pentane is extremely high. structure ατωB97X-D/6-311++G(3df,3pd) level. The simulated frequencies are scaled by 0.945 References [1] Y. Matsuda, Y. Nakayama, N. Mikami, A. Fujii, Phys. Chem. Chem. Phys., 16, 9616, (2014) [2] Y. Matsuda, T. Endo, N. Mikami, A. Fujii, M. Morita, K. Takahashi, J. Phys. Chem. A, 119, 4885 (2015) [3] M. Hachiya, Y. Matsuda, K. Suhara, N. Mikami, and A. Fujii, J. Chem. Phys. 129, 094306 (2008) [4] M. Xie, Y. Matsuda, and A. Fujii, J. Phys. Chem. A. 120, 6351 (2016)

6664 A07

Infrared spectroscopic study for proton transfer from the radical A Molecular Line Survey toward the Nearby Galaxies cation of pentane to water clusters NGC 1068, NGC 253, and IC 342 in the 100 GHz region with the Nobeyama 45-m radiotelescope Tomoya Endo, Yoshiyuki Matsuda, and Asuka Fujii a) b) c) Departement of Chemistry, Graduate School of Science, Tohoku Universiy, 6-3, Aramki-Aoba, Aoba-ku, Sendai, Japan Shuro Takano , Taku Nakajima , Kotaro Kohno , Nanase Haradad), and Eric Herbste) High proton donor abilities of cationic OH and NH have widely been demonstarted by spectroscopic investigations of a)Nobeyama Radio Observatory, National Astronomical Observatory of Japan, Nobeyama, Nagano, Japan, gas phase clusters. Recently, we have clarified the extremely- Department of Astronomical Science, SOKENDAI, Nobeyama, Nagano, Japan, and high proton donor abilities of CH bonds in the radical cations (Present address) Department of Physics, College of Engineering, Nihon University, Koriyama, Japan of amines, ethers, and alcohols, although neutral CH is b)Institute for Space-Earth Environmental Research, Nagoya University, Chikusa-ku, Nagoya, Japan normally regarded as aprotic because of their low proton donor c)Institute of Astronomy, The University of Tokyo, Mitaka, Tokyo, Japan, and abilities.[1-3] The mechanisms for the enhancement of the Research Center for the Early Universe, The University of Tokyo, Bunkyo-ku, Tokyo, Japan proton donor abilities of their cationic CHs are rationalized by d)Academia Sinica Institute of Astronomy and Astrophysics, PO Box 23-141, Taipei, Taiwan the hyperconjugation between CH and the nonbonding orbital e)Department of Chemistry, University of Virginia, PO Box 400319, Charlottesville, USA which is a singly occupied molecular orbital (SOMO). Very + recently, we have reported the infrared (IR) signatures which Fig. 1 (a) Observed IR spectrum of [pentane-(H2O)1] indicate the high proton donor abilities of CH in cationic (b) Simulated vibrational spectrum for the most We report line survey observations toward the nearby galaxies NGC 1068, NGC 253, and IC 342 pentane, hexane, and pentane, although they do not have stable structure ατωB97X-D/6-311++G(3df,3pd) with the Nobeyama 45-m telescope. This is one of the subprojects of the legacy line survey project. nonbonding orbitals.[4] In the present study, we carried out IR level. The simulated frequencies are scaled by 0.945 NGC 1068 is a gas-rich galaxy with an active galactic nucleus (AGN), where large amounts of + spectroscopy of [pentane-(H2O)n] (n=1-3) to examine the gas are falling into the central black hole. The AGN is emitting X-rays and UV radiation. Our proton donor ability of the pentane cation by probing the motivation is to study the effect of the AGN on the molecular abundances. In addition, the gas-rich interaction between its CH bonds and the water clusters. nearby starburst galaxies NGC 253 and IC 342 were also observed for comparison. The survey was Figs. 1 (a) and (b) are the observed IR spectrum of carried out from 85 to 116 GHz (Figure 1). As a result, we detected 19-24 atomic and molecular + [pentane-H2O] and the simulated spectrum of its most stable species in these galaxies including new detections [1,2]. NGC 1068 and NGC 253 have already structure inserted in the figure. In this structure, the proton of been observed with the IRAM 30-m telescope [3,4], but our spatial resolution is higher than that of cationic pentane is shared between the pentyl radical (C5H11) and the water molecule. The simulated spectrum agrees with the IRAM 30-m telescope. Thus, we could more selectively study the molecular abundances in the the observed one. The observed and simulated free OH (ν1 and circumnuclear disk (CND) around the AGN. The species CN, HCN, and HC3N were found to be ν3) frequencies indicate the water molecule has the hydronium more abundant in NGC 1068 than in NGC 253 and IC 342. However, CH3CCH was not detected ion character, though the proton is not completely transferred. and is deficient in NGC 1068. This result is in sharp contrast to the abundant CH3CCH in NGC 253 Figs. 2 (a) and (b) show the observed IR spectrum of and IC 342. Further results of the analyses will be presented. + Fig.2 (a) Observed IR spectrum of [pentane- [pentane-(H2O)2] and the simulated spectrum of its most (H2O)2] (b) Simulated spectrum for the most stable stable structure. In the observed IR spectrum, a broad feature structure at ωB97X-D/6-311++G(3df,3pd) level. -1 appears in the frequency region lower than 2800 cm . This The simulated frequencies are scaled by 0.945 broad feature can be explained by the vibration of the proton which is transferred from the pentane cation to the water + moiety. Hence, we have concluded that [pentane-(H2O)2] forms the protontransferred structure. Figs. 3 (a) and (b) show the observed IR spectrum of + [pentane-(H2O)3] and the simulated spectrum of the most stable proton-transferred structure. In the observed spectrum, an intense broad band is observed in addition to the νCH, ν1, and ν3 bands. This broad band is attributed to the modes involving the vibration of the transferred proton. The proton transfer from CH of the pentane cation to the water clusters occurs at n≥2. Since the phenol cation requests at least three water molecules for the proton transfer, the Fig.3 (a) Observed IR spectrum of [pentane- + present results demonstrate that the proton donor ability of CH (H2O)3] (b) Simulated spectrum for the most stable in cationic pentane is extremely high. structure ατωB97X-D/6-311++G(3df,3pd) level. The simulated frequencies are scaled by 0.945 References Figure 1. Spectra toward NGC 1068, IC 342, and NGC 253 [1] Y. Matsuda, Y. Nakayama, N. Mikami, A. Fujii, Phys. Chem. Chem. Phys., 16, 9616, (2014) [2] Y. Matsuda, T. Endo, N. Mikami, A. Fujii, M. Morita, K. Takahashi, J. Phys. Chem. A, 119, 4885 (2015) References [3] M. Hachiya, Y. Matsuda, K. Suhara, N. Mikami, and A. Fujii, J. Chem. Phys. 129, 094306 (2008) [1] Nakajima et al., Astrophysical Journal Letters, 728, L38 (2011). [2] Takano et al. in Astronomical Society of [4] M. Xie, Y. Matsuda, and A. Fujii, J. Phys. Chem. A. 120, 6351 (2016) the Pacific Conference Series, 476, 193 (2013). [3] Aladro et al. Astronomy & Astrophysics, 549, A39 (2013). [4] Aladro et al. Astronomy & Astrophysics, 579, A101 (2015).

64 6765 A08

Impact of 2-methylbutanal photochemistry in the atmosphere

Kharazmi, Aa), Shaw, M Fb), Jordan, M.J.T.b), Kable, S.H.b)

a) University of New South Wales, Sydney, Australia b) University of Sydney, Sydney, Australia

Aldehydes and ketones are major components of oxidized molecules in the atmosphere. The photochemistry of these compounds has a significant contribution in atmospheric chemistry. Norrish Types I and II (NT-I and NT-II) are well-known pathways to decompose these molecules.

Despite many years of research on the photochemistry of these molecules, the fundamental photochemical mechanisms of these pathways are still a controversial subject due to their complex nature. In NT-I reaction, the molecule dissociates to the free radicals, HCO and alkyl, on the triplet state. In the NT-II reaction, enol and alkene are formed from a 6-membered ring transition state following a 1-5 hydrogen shift from the carbon centre to the oxygen centre. In the TF reaction, molecule dissociates to H2, CO and alkene on the S0 state. In the atmosphere, the fate of products of NT-I, NT-II and TF are different. For instance, the alkene produced form NT-II can participate in ozonolysis reaction and enol is suggested to produce organic acids. In contrast to NT-I reaction, in NT-II, it is not yet well understood that which states, S0, T1 or both, are involved in the photolysis mechanism. The triple fragmentation channel contributes to formation of H2 in the atmosphere.

Our aim is to scrutinize the photochemical mechanism of 2-methylbutanal by investigating wavelength dependent photochemistry of this molecule in the 300 - 330 nm region. Thus, the quantum yields of products are calculated in the photolysis of 2-methylbutanal with FTIR spectroscopy.

6866 A09

Impact of 2-methylbutanal photochemistry in the atmosphere Ultrafast photoelectron spectroscopy of electron-core wave

packet in Rydberg N2 by single-order laser high harmonics a) b) b) b) Kharazmi, A , Shaw, M F , Jordan, M.J.T. , Kable, S.H. Mizuho Fushitania), Yuto Toidaa), François Légaréb), and Akiyoshi Hishikawac) a) University of New South Wales, Sydney, Australia a)Depart. of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan b) University of Sydney, Sydney, Australia b)INRS-EMT, 1650 Bld. Lionel Boulet, Varennes, Québec, Canada c)Research Center of Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan Aldehydes and ketones are major components of oxidized molecules in the atmosphere. The photochemistry of these compounds has a significant contribution in atmospheric chemistry. Recent advances of laser high-order harmonics generation have enabled us to employ ultrashort Norrish Types I and II (NT-I and NT-II) are well-known pathways to decompose these molecules. laser pulse as a probe for accessing atomic/molecular Rydberg states lying in EUV [1-3]. Rydberg wave packets, formed by coherent superposition of highly excited Rydberg states, exhibit dynamics Despite many years of research on the photochemistry of these molecules, the fundamental on a variety of time scales depending on the effective principle quantum number (neff). The orbit photochemical mechanisms of these pathways are still a controversial subject due to their complex period of Rydberg states with neff ~ 10 becomes femto- to pico-second time scales on which the nature. In NT-I reaction, the molecule dissociates to the free radicals, HCO and alkyl, on the triplet dynamics corresponds to nuclear motions such as vibration and rotation. Therefore, unlike atomic state. In the NT-II reaction, enol and alkene are formed from a 6-membered ring transition state systems, such molecular Rydberg wave packet exhibits more complex dynamics due to the interplay following a 1-5 hydrogen shift from the carbon centre to the oxygen centre. In the TF reaction, between electron and nuclear degrees of freedom. Here, we discuss Rydberg wave packets molecule dissociates to H2, CO and alkene on the S0 state. In the atmosphere, the fate of products dynamics of N2 in different electronic states by time-resolved photoelectron spectroscopy with of NT-I, NT-II and TF are different. For instance, the alkene produced form NT-II can participate in single-order harmonics at 80 nm. ozonolysis reaction and enol is suggested to produce organic acids. In contrast to NT-I reaction, in A part of the output of a regenerative Ti:sapphire laser system (800 nm, 2 mJ/pulse, 1 kHz) was NT-II, it is not yet well understood that which states, S0, T1 or both, are involved in the photolysis frequency-doubled by a BBO crystal to generate an UV pulse at 400 nm. The UV pulse was focused mechanism. The triple fragmentation channel contributes to formation of H2 in the atmosphere. by a plano-convex lens into a gas cell filled with Kr (~10 Torr) for high-order harmonic generation. Ultrashort EUV pulses at ~80 nm were obtained as the 5th order harmonics by filtering with an Our aim is to scrutinize the photochemical mechanism of 2-methylbutanal by investigating indium foil (0.1 µm) the co-propagating fundamental and harmonics of other orders [4,5]. The wavelength dependent photochemistry of this molecule in the 300 - 330 nm region. Thus, the single-order harmonics covers several absorption peaks of N2 in the bandwidth (~ 0.10 eV) to create quantum yields of products are calculated in the photolysis of 2-methylbutanal with FTIR a wave packet consisting of npπ(v = 0) (n = 9-13), 9pσ(0), 10pσ(0), 6pπ(1), 5pπ(2), 5pσ(2), 4pπ(4), 2 + 2 spectroscopy. 8f(0), and 9f(0) Rydberg states converging to X Σg and 3dδ(1), 3dσ(2) and 4sσ(1) to A Πu of molecular nitrogen [6]. Time evolution of the Rydberg wave packet is probed by a time-delayed + 2 + 2 ultrashort NIR pulse (800 nm) ionizing to the N2 X Σg as well as A Πu states. Photoelectrons generated by the probing process were detected by using a magnetic bottle type spectrometer with the typical electron energy resolution of E/ΔE = 50 for E < 100 eV. The recorded photoelectron spectrum exhibits seven peaks corresponding to the vX = 0–4 + 2 + + 2 vibrational levels of N2 X Σg and to the vA =0-1 of N2 A Πu. The three extra peaks, vX = 2-4 levels, were identified by comparing with the conventional photoelectron spectra obtained with a He II light source. The time evolution of each peak exhibits the modulation in intensity with a period of ~300 fs. The oscillation for vX = 4 starts with a minimum while the signal intensity of the other 2 + peaks shows a maximum at Δt = 0 fs. Among the Rydberg levels converging to X Σg pumped by 2 the EUV pulse, the 4pπ(4) level is strongly coupled to the 3dδ(1) level converging to A Πu [6], resulting in the mixing of the 4pπ(4) and 3dδ(1) wavefunctions with the same or opposite sign. The phase inversion of the oscillatory behavior for vX = 4 can be attributed to the opposite signs of the 4pπ(4) wavefunction. The present study clearly demonstrates the importance of the interplay between nuclear and electron motions for the deeper understanding of molecular Rydberg wave packet dynamics.

[1] T. Okino et al., Sci. Adv., 1, e1500356 (2015). [2] E. R. Warrick et al., J. Phys. Chem., 120, 3165 (2016). [3] M. Eckstein et al., Phys. Rev. Lett., 116, 163003 (2016). [4] M. Fushitani, A. Matsuda, and A. Hishikawa, Opt. Express, 19, 9600 (2011). [5] M. Fushitani and A. Hishikawa, Struct. Dyn., 3, 062602 (2016). [6] K. P. Huber et al., J. Chem. Phys., 131, 084301 (2009).

66 6967 A10

Photodissociation Studies of Alkyl Peroxy Radicals

Erin N. Sullivana), Bethan Nicholsa), and Daniel M. Neumarka) a)Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

Alkyl peroxy radicals are relevant chemical species in combustion and atmospheric chemistry processes. In the troposphere, they can contribute to net ozone production, and in combustion chemistry, they are important reactive intermediates.1,2 In order to understand how these species play a larger role in these two chemical arenas, examining the unimolecular dissociation dynamics of alkyl peroxy radicals can provide useful insight into the reactivity of these molecules. The simplest alkyl peroxy radicals, methyl peroxy (CH3OO) and ethyl peroxy (C2H5OO), were examined using fast beam photofragment translational spectroscopy to identify the products formed and investigate the dissociation dynamics when these radicals absorb a 248 nm photon. A fast beam - - of CH3OO or C2H5OO anions were photodetached to generate neutral radicals that were subsequently dissociated using UV photons. Coincident detection of the photofragments position and arrival times allows for determination of mass, kinetic energy, and angular distributions for both two-body and three-body dissociation events. CH3OO exhibited predominantly two-body 1 dissociation through repulsive O loss resulting in the formation of O ( D) + CH3O with high kinetic energy release. In addition, a minor three-body channel resulting in the formation of H + O + CH2O was also observed.

C2H5OO exhibited more complex dissociation dynamics. O loss and OH loss occurred in roughly equivalent amounts, with O loss occurring again via a repulsive process. OH loss was proposed to form on an excited state surface. A minor two-body channel leading to the formation of some combination of O2 + C2H5 and HO2 + C2H4 was also observed and attributed to a ground state dissociation pathway following internal conversion. Finally, multiple three-body dissociation channels were detected leading to the production of H + O + CH3CHO and CH3 + O + CH2O. Both channels exhibited bimodal kinetic energy distributions indicating two different mechanisms both involving O loss followed by alkoxy dissociation over a barrier.

References:

1. P. D. Lightfoot, R. A. Cox, J. N. Crowley, M. Destriau, G. D. Hayman, M. E. Jenkin, G. K. Moortgat, and F. Zabel, Atmospheric Environment 26A (10), 1805-1961 (1992).

2. J. Zador, C. A. Taatjes, and R. X. Fernandes, Progress in Energy and Combustion Science 37 (4), 371-421 (2011).

7068 A11

Photodissociation Studies of Alkyl Peroxy Radicals Molecular constants determination for F2P(S)NCS by

Erin N. Sullivana), Bethan Nicholsa), and Daniel M. Neumarka) Fourier transform microwave spectroscopy and quantum chemical calculation a)Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA Nobuhiko Kuzea), Shinichiro Watanabea), Yoshiyuki Kawashimaa), and Alkyl peroxy radicals are relevant chemical species in combustion and atmospheric chemistry b) processes. In the troposphere, they can contribute to net ozone production, and in combustion Xiaoqing Zeng , chemistry, they are important reactive intermediates.1,2 In order to understand how these species play a larger role in these two chemical arenas, examining the unimolecular dissociation dynamics a)Department of Materials and Life Sciences, Faculty of Science and Technology Sophia University, of alkyl peroxy radicals can provide useful insight into the reactivity of these molecules. The 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan simplest alkyl peroxy radicals, methyl peroxy (CH3OO) and ethyl peroxy (C2H5OO), were b)College of Chemistry, Chemical Engineering and Materials Science, Soochow University, examined using fast beam photofragment translational spectroscopy to identify the products formed Suzhou, P. R. China and investigate the dissociation dynamics when these radicals absorb a 248 nm photon. A fast beam - - of CH3OO or C2H5OO anions were photodetached to generate neutral radicals that were Rotational constants, centrifugal distortion constants, nuclear quadruple coupling constants for subsequently dissociated using UV photons. Coincident detection of the photofragments position 14 and arrival times allows for determination of mass, kinetic energy, and angular distributions for both N atom of difluorothiophosphoryl isothiocyanate (F2P(S)NCS) of normal species were determined two-body and three-body dissociation events. CH3OO exhibited predominantly two-body by observing its Molecular beam-Fourier transform microwave spectroscopy (MB-FTMW) in the 1 dissociation through repulsive O loss resulting in the formation of O ( D) + CH3O with high kinetic frequency range of 4 to 10 GHz in the ground vibrational state. The rotational constants were A = energy release. In addition, a minor three-body channel resulting in the formation of H + O + CH2O was also observed. 2679.2671(2), B = 863.6736(2), and C = 753.5564(2) MHz, respectively, where the errors in parentheses are 1. The comparison of the observed spectroscopic parameters with the calculated C2H5OO exhibited more complex dissociation dynamics. O loss and OH loss occurred in roughly equivalent amounts, with O loss occurring again via a repulsive process. OH loss was proposed to ones led to the conclusion that the assigned spectrum was due to the syn form which is an NCS group form on an excited state surface. A minor two-body channel leading to the formation of some were found to be at the syn position with respect to the P=S bond. This conformational preference combination of O2 + C2H5 and HO2 + C2H4 was also observed and attributed to a ground state dissociation pathway following internal conversion. Finally, multiple three-body dissociation will be influenced to the decomposition process to produce the radicals. channels were detected leading to the production of H + O + CH3CHO and CH3 + O + CH2O. Both The values of the theoretical rotational constants by the ab initio calculations at the MP2 level of channels exhibited bimodal kinetic energy distributions indicating two different mechanisms both theory are in agreement with the observed ones. On the other hand, theoretical values of nuclear involving O loss followed by alkoxy dissociation over a barrier. quadruple coupling constants are about 30% smaller than the observed values. We are observing the References: isotopomers of this compound such as 34S, 13C and 15N species. 1. P. D. Lightfoot, R. A. Cox, J. N. Crowley, M. Destriau, G. D. Hayman, M. E. Jenkin, G. K. Moortgat, and F. Zabel, Atmospheric Environment 26A (10), 1805-1961 (1992).

2. J. Zador, C. A. Taatjes, and R. X. Fernandes, Progress in Energy and Combustion Science 37 (4), 371-421 (2011).

Fig. syn form of F2P(S)NCS

68 7169 A12

New mass spectrometric methods for detecting over 24 halogenated species simultaneously at ambient pressure

Xucheng Hea), Siddharth Iyerb), Putian Zhoua), Qiaozhi Zhaa), Lauri Ahonena), Chao Yana), Nina Sarnelaa), Yonghong Wanga), Monica Passanantia), Wei Niec,a), Mikael Ehna), Markku Kulmalaa), Tuija Jokinena), Heikki Junninena), Matti Rissanena), and Mikko Sipiläa)

a)Department of Physics, University of Helsinki, FI-00014, Helsinki, Finland b)Department of Chemistry, University of Helsinki, FI-00014, Helsinki, Finland c)School of Atmospheric Sciences, Nanjing University, 210046, Nanjing, China

Halogenated species have significant impact on atmospheric composition, including catalytic ozone [1] destruction and influence on HOx and NOx cycles . Halogens are also involved in marine and coastal new particle formation, a process that can ultimately affect Earth’s radiation balance. However, the exact processes governing halogen chemistry and halogen mediated new particle formation have been puzzling the community for years. One of the major difficulties in understanding these processes has been the lack of techniques able to measure inorganic halogenated radicals and stable species simultaneously both in laboratory and ambient conditions[1]. This is because previous spectroscopic and mass spectrometric methods utilized could only measure one, or a few halogenated species at once, while most of the halogenated species existing in the atmosphere were likely un-measurable. Here we present new chemical ionization (CI) mass spectrometric methods to measure over 24 halogenated species simultaneously at an ambient pressure.

- - - Nitrate (NO3 ), iodide (I ) and bromide (Br ) reagent ions were used with a soft X-ray based chemical ionization inlet system and an Atmospheric Pressure interface Time Of Flight Mass Spectrometer (CI- APi-TOF) to measure different halogenated species. The nitrate CI deployed in Mace Head has [2] uncovered a nucleation process via sequential HIO3 addition in Mace Head, coast of Ireland . In addition, according to a set of laboratory experiments, the iodide based CI was shown to be able to measure iodinated and chlorinated species, as illustrated in figure 1, while the possibility in measuring brominated species will also be presented. The combination of these new methods has enabled us to study the formation mechanism of HIO3 in detailed flow tube experiments. One of the pathways confirmed by previous quantum chemical calculations suggested that the reaction between OIO and [3] OH forms HIO3 , while two novel formation pathways were implied by the current experiments and will be presented in Free Radical meeting.

Figure 1. Mass defect plot of A) using an iodide CI to measure iodinated species. B) using iodide chemical ionization to measure chlorinated species. Tables list speculated measured neutral species. References [1] Sherwen, T., Schmidt, J. A., … Ordóñez, C. ACP, 16(18), 12239–12271(2016). [2] Sipilä, M., Sarnela, N., … O’Dowd, C. Nature, 537(7621), 4–6(2016). [3] Plane, J. M. C., Joseph, D. M., … Francisco, J. S. JPCA, 110(1), 93–100(2006).

7270 A13

New mass spectrometric methods for detecting over 24 Development of Time- and Angle-Resolved-Resolved PhotoePhotoelectronlectron halogenated species simultaneously at ambient pressure Spectroscopy using Vacuum Ultraviolet Light source at 29.5 eV

Xucheng Hea), Siddharth Iyerb), Putian Zhoua), Qiaozhi Zhaa), Lauri Ahonena), Chao J. Nishitani, C. W. West, C. Higashimura, and T. Suzuki Yana), Nina Sarnelaa), Yonghong Wanga), Monica Passanantia), Wei Niec,a), Mikael Ehna), Markku Kulmalaa), Tuija Jokinena), Heikki Junninena), Matti Rissanena), and Department of Chemistry, Graduate School of Science, Kyoto University, KitashirakawaKitashirakawa Oiwake-Oiwake-cho, Mikko Sipiläa) Sakyo-Ku, Kyoto 606-8502, Japan a)Department of Physics, University of Helsinki, FI-00014, Helsinki, Finland Ultrafast electronic dynamics in gases and solids have been explored using time- and b)Department of Chemistry, University of Helsinki, FI-00014, Helsinki, Finland angleangle-resolved-resolved photoemission spectroscopy (TARPES), while liquids have been excluded from the c)School of Atmospheric Sciences, Nanjing University, 210046, Nanjing, China target of TARPES owing to experimental difficulties. The use of liquid microjets enables the introduction of volatile liquids into a vacuum chamber and so photoelectrophotoelectron spectroscopy of Halogenated species have significant impact on atmospheric composition, including catalytic ozone aqueous solution. For probing the entire electronic dynamics including the internal conversion to the [1] destruction and influence on HOx and NOx cycles . Halogens are also involved in marine and coastal ground electronic state, a high probe photon energy that is greater than the ionization energy of the new particle formation, a process that can ultimately affect Earth’s radiation balance. However, the target molecule is required. Thus, we have developed a photoelectron spectrometer of liquid exact processes governing halogen chemistry and halogen mediated new particle formation have been microjets using a vacuum ultraviolet (VUV) light source based on laser high harmonic generation puzzling the community for years. One of the major difficulties in understanding these processes has (HHG). The fundamental output of a one-box 1-kHz Ti:sapphire laser with 35 fs pulse duration was been the lack of techniques able to measure inorganic halogenated radicals and stable species used to generate high harmonics in Kr gas, from which the 19th harmonic (42 nm, 29.5 eV) was simultaneously both in laboratory and ambient conditions[1]. This is because previous spectroscopic selected using two SiC/Mg mirrors. Selection of a single harmonic order by the use of mirrors and mass spectrometric methods utilized could only measure one, or a few halogenated species at ensured a constant photon flux as the laser polarization was rotated, which enabled reliable once, while most of the halogenated species existing in the atmosphere were likely un-measurable. measurements of polarization dependence of photoemission. Here we present new chemical ionization (CI) mass spectrometric methods to measure over 24 Figure 1 shows the angle-resolved-resolved photoemission spectroscopy (A(ARPES) of liquid water [1]. The halogenated species simultaneously at an ambient pressure. observed spectra were deconvoluted into the spectral contributions of liquid water, water vapor, and background, and the photoemission anisotropy parameters of liquid water were determined for three - - - Nitrate (NO3 ), iodide (I ) and bromide (Br ) reagent ions were used with a soft X-ray based chemical different valence orbitals. These anisotropy parameters are in quantitative agreement with ionization inlet system and an Atmospheric Pressure interface Time Of Flight Mass Spectrometer (CI- predictions based on Monte-Carlo simulations of electron scattering in liquid water [2]. APi-TOF) to measure different halogenated species. The nitrate CI deployed in Mace Head has Figure 2 shows the time-resolved photoemission spectroscopy (TRPES) of pyrazine with a 266 [2] uncovered a nucleation process via sequential HIO3 addition in Mace Head, coast of Ireland . In nm pump pulse and the 29.5 eV VUV probe pulse [3]. The S1(n,*) excited state population created addition, according to a set of laboratory experiments, the iodide based CI was shown to be able to by ultrafast internal conversion from the S2(,*) statestate decays to the S0 state in about 20 ps. measure iodinated and chlorinated species, as illustrated in figure 1, while the possibility in measuring Similarly,Similarly, TRPES of 1,3--cyclohexadienecyclohexadiene revealed the photochemical ring-opening reaction to form brominated species will also be presented. The combination of these new methods has enabled us to 1,3,5-hexatriene-hexatriene in real time [3].[3]. These results clearly demonstrate the utility of the HHG light study the formation mechanism of HIO3 in detailed flow tube experiments. One of the pathways source and suggest that UV-pump VUV-VUV-probe experiments of liquid microjets are feasible.feasible. confirmed by previous quantum chemical calculations suggested that the reaction between OIO and OH forms HIO [3], while two novel formation pathways were implied by the current experiments and 3 1.2 (a) 1b1g 6ag Pyrazine spectra 1 (gas) will be presented in Free Radical meeting. P-pol. b1 -10 ps 1.0 fit P-pol. 0.8 2 ps S-pol. 1.2 1b 6a 1b (a) 1g g 0.8 fit S-pol. 2 0.4 -10 ps 1b1(Liq) 3 2 ps a1 0.80.0 0.6 Liquid beam

Intensity (arb. units) (arb. Intensity 0.02 0.4 (b) Difference spectrum 0.4 S e− 0.00.00 Intensity (arb. units) (arb. Intensity Intensity units)(arb. 0.2 P Excited state signal 0.0 -0.02 Ground state bleach 84 1612 20 18 20 22 24 electron binding energy (eV) Photoelectron kinetic energy (eV) Differential signal (arb. units)

Figure 1. Mass defect plot of A) using an iodide CI to measure iodinated species. B) using iodide chemical Fig. 1 ARPES of liquid water using P- and Fig. 2 TRPES of gaseous pyrazine with ionization to measure chlorinated species. Tables list speculated measured neutral species. SS-polarization-polarization of VUV probe. UV-pump VUV-probe. References [1] Sherwen, T., Schmidt, J. A., … Ordóñez, C. ACP, 16(18), 12239–12271(2016). RefReferenceserences [2] Sipilä, M., Sarnela, N., … O’Dowd, C. Nature, 537(7621), 4–6(2016). [1[1] J. Nishitani, et al., Struct. Dynam., 4, 044014 (2017). [3] Plane, J. M. C., Joseph, D. M., … Francisco, J. S. JPCA, 110(1), 93–100(2006). [2][2] S. Hartweg, et al., Phys. Rev. Lett., 118, 103402 (2017). [3[3] J. Nishitani et al., Chem. Phys. Lett., submitted.

70 7371 A14

Photochemical reaction of 2,3-dihydrofuran and its derivatives with infrared free electron laser

E. Yuda, M. Matsubara, F. Osada, Y. Negishi, K. Ito, W. Maruki, and K. Tsukiyama

Department of Chemistry, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo, 162-8601 Japan

Infrared Free Electron Laser at Tokyo University of Science (FEL-TUS) is an accelerator-based laser tunable in the mid-infrared region.It possesses a unique temporal pulse structure containing the train of pico-second pulses. High photon density of FEL can induce various reactions based on Infrared multi photon absorption (IRMPA). Our group has been researching IRMPA of simple organic molecules with FEL-TUS in the gas phase. 2,3-dihydrofuran (2,3-DHF) is five-membered cyclic ether. The thermal isomerization from 2,3-DHF to crotonaldehyde (CA) and cyclopropane carboxaldehyde (CPCA) has been reported in 1947 [1]. In this symposium, we will present the results of 1. isomerization reactions induced by IRMPA in the 2,3-DHF and 2. photosensitized reactions induced by collisions of 2,3-DHF with vibrationally hot CClF3. Sample gas in the stainless cell (length: 125 mm, internal diameter: 25 mm, window material: BaF2) was irradiated with FEL-TUS (5 Hz, 3-12 mJ/pulse) focused by a BaF2 lens (f = 300 mm). Gas Chromatograph Mass Spectrometer was used to analyze the products after FEL irradiation quantitatively. 1. The gas chromatogram after FEL irradiation to 2,3-DHF at 1590 cm-1 (C=C stretching mode) revealed that 2,3-DHF was converted to CA and CPCA (Fig. 1(a)). The isomerization rates for two products are plotted as a function of the FEL wavenumber in Fig. 2. The FEL wavenumber giving the maximum isomerization rate is located ~ 40 cm-1 lower than the absorption peak, which indicates that the isomerization from 2,3-DHF to CA and CPCA is caused by the IRMPA reaction. -1 2. The mass spectra after FEL irradiation to a mixture of 2,3-DHF and CClF3 at 1080 cm (C-F stretching mode) revealed that the photosensitized reaction of 2,3-DHF with vibrationally highly excited CClF3 yielded furan exclusively (Fig. 1(b)). No trace of the isomerization reaction was recognized. We will present the results of 2,5-dihydrofuran and 5-methyl-2,3-dihydrofuran that are derivatives of 2,3-DHF.

Fig.1 The gas chromatogram after FEL irradiation Fig.2 The isomerization rates for (a) CPCA (a) to 2,3-DHF at 1590 cm-1 and (b) to 2,3-DHF and (b) CA compared with (c) IR absorption and CClF3 at 1080 cm-1 spectra of 2,3-DHF

References [1] C. L. Wilson, J. Chem. Soc., 69, 3002 (1947).

7472 A15

Photochemical reaction of 2,3-dihydrofuran and its derivatives Photochemical Production of H2 form Aldehydes with infrared free electron laser a) b) a) b) Aaron Harrison , Miranda Shaw , Alireza Kharazmi , Meredith Jordan a) E. Yuda, M. Matsubara, F. Osada, Y. Negishi, K. Ito, W. Maruki, and K. Tsukiyama and Scott Kable

a) Department of Chemistry, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo, 162-8601 Japan School of Chemistry, University of New South Wales b)School of Chemistry, University of Sydney Infrared Free Electron Laser at Tokyo University of Science (FEL-TUS) is an accelerator-based laser tunable in the mid-infrared region. It possesses a unique temporal pulse structure containing the train of pico-second pulses. High photon density of FEL can induce various reactions based on Infrared multi photon absorption (IRMPA). Our group has been researching IRMPA of simple Atmospheric models provide the predictive power to assist in control, regulation and understanding organic molecules with FEL-TUS in the gas phase. of important issues such as climate change, urban pollution and the recovery of the Antarctic ozone 2,3-dihydrofuran (2,3-DHF) is five-membered cyclic ether. The thermal isomerization from hole. Models, of course, are only as good as the reactions comprise them. But the atmosphere is 2,3-DHF to crotonaldehyde (CA) and cyclopropane carboxaldehyde (CPCA) has been reported in incredibly complex – over 2 billion tonnes of organic material, with over a million chemical 1947 [1]. In this symposium, we will present the results of 1. isomerization reactions induced by structures, is emitted to the atmosphere every year. Models are, accordingly, also very complex; for IRMPA in the 2,3-DHF and 2. photosensitized reactions induced by collisions of 2,3-DHF with example the Master Chemical Mechanism chemical model for the atmosphere (U. Leeds, UK) vibrationally hot CClF3. contains over 17,000 reactions. Sample gas in the stainless cell (length: 125 mm, internal diameter: 25 mm, window material: BaF2) was irradiated with FEL-TUS (5 Hz, 3-12 mJ/pulse) focused by a BaF2 lens (f = 300 mm). Photochemical reactions carried out in a molecular beam are ideal for characterizing how the energy Gas Chromatograph Mass Spectrometer was used to analyze the products after FEL irradiation is deposited into the products, and the collision-free environment ensures that the reaction is a quantitatively. primary process. However, quantum yields are very difficult to measure (we know a reaction 1. The gas chromatogram after FEL irradiation to 2,3-DHF at 1590 cm-1 (C=C stretching mode) happens for sure, but not whether it is important!). Reactions in gas bulbs can be used to determine revealed that 2,3-DHF was converted to CA and CPCA (Fig. 1(a)). The isomerization rates for two absolute quantum yields, but untangling the complex chemistry is difficult (we know how much products are plotted as a function of the FEL wavenumber in Fig. 2. The FEL wavenumber giving products are formed, but not how). The combination of the two techniques can yield both the maximum isomerization rate is located ~ 40 cm-1 lower than the absorption peak, which mechanism and importance. indicates that the isomerization from 2,3-DHF to CA and CPCA is caused by the IRMPA reaction. -1 2. The mass spectra after FEL irradiation to a mixture of 2,3-DHF and CClF3 at 1080 cm (C-F In this poster, we will explain some of our recent studies on reaction mechanisms for laser-induced stretching mode) revealed that the photosensitized reaction of 2,3-DHF with vibrationally highly photochemistry of carbonyls, both in molecular beams and gas bulbs. Atmospheric models excited CClF3 yielded furan exclusively (Fig. 1(b)). No trace of the isomerization reaction was underestimate the observed amount of H2 in the atmosphere. The combination of H2 production in recognized. We will present the results of 2,5-dihydrofuran and 5-methyl-2,3-dihydrofuran that are photolysis of acetaldehyde in a beam, and ketene production in the bulb leads us to conclude that derivatives of 2,3-DHF. the missing H2 production might arise from photochemistry of carbonyls.

Fig.1 The gas chromatogram after FEL irradiation Fig.2 The isomerization rates for (a) CPCA (a) to 2,3-DHF at 1590 cm-1 and (b) to 2,3-DHF and (b) CA compared with (c) IR absorption and CClF3 at 1080 cm-1 spectra of 2,3-DHF

References [1] C. L. Wilson, J. Chem. Soc., 69, 3002 (1947).

72 7573 A16

Rydberg-Rydberg far infrared transition of NO

Kento Nishimuraa), Shoma Hoshinob), and Koichi Tsukiyamaa)

a)Graduate School of Chemical Sciences and Technology, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601, Japan. b)Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-1-2 Ookayama, Meguro, Tokyo, 152-8550, Japan.

Our group has been investigating the characteristics of Amplified Spontaneous Emission (ASE) in the Rydberg states of NO and suggesting that stimulated emission between nearby Rydberg states was playing an important role as a radiative process [1]. Recently, we reported the directional emission in the far infrared region and supposed that the observed emissions were stimulated transition by blackbody radiation (BBR) at room temperature. In this work, we report the far infrared emission in the 60 – 110 µm region from higher Rydberg states, 14p and 15p, of NO for the first time. The possible optical (de)excitation processes among Rydberg states involving BBR will be discussed. The 14p and 15p Rydberg states were excited via the A 2Σ+ state by using an optical-optical double resonance technique. The pump and probe lasers were temporally and spatially overlapped and were introduced into a 17 cm stainless steel cell containing NO (~5 Torr). The forward propagating emission was dispersed with a monochromator, and was detected by a germanium photoconductor. Figure 1 shows the dispersed emission spectra from the 14p and 15p states. The energy level diagram of the relevant Rydberg states of NO is shown in Figure 2. Referring to the transition dynamics from 13f and 14f states of NO, we assigned the emission around 66 and 88 µm from 14p, and around 88 and 113 µm from 15p as the transition from the cascade 12g → 11f, 13f → 12g, 13g → 12f, and 14f → 13g transitions, respectively. The emission from the laser prepared 15p to 14f and 14p to 13f expected at ~400 and ~300 µm are out of range. In the presence of thermal radiation, BBR induced transition rate Kn'l',nl is given by 1 Kn'l',nl = An'l',nl exp(!ωn'l',nl / kT )−1 where An'l',nl is Einstein coefficient [2]. This equation describes the relation between the spontaneous emission and the stimulated emission. In a case of the far infrared emission around 88 and 113 µm at room temperature, the value of K14f,13g / A14f,13g and K13g,12f / A13g,12f are ~ 1.91 and ~ 1.33, while the value is 3.8 × 10-11 for the near infrared emission at 2 µm. In other words, contribution of BBR to the state to state transitions can be dominant for optical transitions in the far infrared region.

Fig. 1. (Upper panel) The dispersed emission Fig. 2. Grotrian diagram of Rydberg states of spectra from the 15p (v15p = 0, N14p = 2, =0) NO. The upward solid arrows indicate the state. (Lower panel) The dispersed emission double-resonant excitation scheme for the 2 spectra from 14p (v14p = 0, N14p = 2, =0) state.ℒ excitation from X Π ground state to the 14p and 15p Rydberg state. The downward solid arrows References ℒ are transition channels observed in Fig. 1. [1] Ogi et al., Chem. Phys. Lett. 436, 303 (2007). [2] Gallagher et al., Appl. Phys. Lett. 34, 369 (1979).

7674 A17

Rydberg-Rydberg far infrared transition of NO Three-dimensional Potential energy surfaces of Rg-CO (Rg:He, Ne, Ar, Kr) a) b) a) Kento Nishimura , Shoma Hoshino , and Koichi Tsukiyama Kohei Ohtsukia), Taito Ishibashi a), Yasuki Endob), and Yoshihiro Sumiyoshia) a)Graduate School of Chemical Sciences and Technology, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601, Japan. a) b) Graduate School of Science and Technology, Gunma University, Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-1-2 Ookayama, Meguro, Tokyo, 4-2 Aramaki, Maebashi, Gunma 371-8510, Japan 152-8550, Japan. b)Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan

Our group has been investigating the characteristics of Amplified Spontaneous Emission (ASE) in A three-dimensional intermolecular potential energy surfaces (3D IPESs) of the Rg-CO complexes the Rydberg states of NO and suggesting that stimulated emission between nearby Rydberg states was (Rg: He, Ne, Ar, Kr) have been determined by utilizing previously reported spectroscopic data. playing an important role as a radiative process [1]. Recently, we reported the directional emission in For Ar-CO, for example, 971 transition frequencies by MW [1], millimeter- and submillimeter-wave the far infrared region and supposed that the observed emissions were stimulated transition by [2], and IR spectroscopy [3] have been reproduced simultaneously within experimental accuracies. blackbody radiation (BBR) at room temperature. In this work, we report the far infrared emission in the 60 – 110 µm region from higher Rydberg states, 14p and 15p, of NO for the first time. The possible A free rotor model Hamiltonian considering all the freedom of motions for an atom-diatom optical (de)excitation processes among Rydberg states involving BBR will be discussed. system was used to calculate vibration-rotation energies. The 3D IPESs by ab initio calculations at The 14p and 15p Rydberg states were excited via the A 2Σ+ state by using an optical-optical double the CCSD(T)-F12b/aug-cc-pV5Z level of theory were parameterized by a model function consisting resonance technique. The pump and probe lasers were temporally and spatially overlapped and were of 46 potential parameters and they were used as initial values in the least-squares analysis. In introduced into a 17 cm stainless steel cell containing NO (~5 Torr). The forward propagating total, 9 potential parameters for He-CO, 20 for Ne-CO and Ar-CO, and 13 for Kr-CO, were emission was dispersed with a monochromator, and was detected by a germanium photoconductor. optimized to reproduce all the experimental data, where pure rotational transition frequencies of Figure 1 shows the dispersed emission spectra from the 14p and 15p states. The energy level diagram Rg-13CO were included by considering the effect of the change of the center of mass of the of the relevant Rydberg states of NO is shown in Figure 2. Referring to the transition dynamics from monomer. It is found that the IPESs of Ne, Ar, and Kr-CO have the most stable configuration at θ 13f and 14f states of NO, we assigned the emission around 66 and 88 µm from 14p, and around 88 = 90°, while no minimum is found around the configuration at θ = 180°(Rg⋅⋅⋅CO). The IPES of and 113 µm from 15p as the transition from the cascade 12g → 11f, 13f → 12g, 13g → 12f, and 14f He-CO, on the other hand, shows quite isotropic character, where the IPES has almost the same → 13g transitions, respectively. The emission from the laser prepared 15p to 14f and 14p to 13f potential energy values for the configurations from θ = 0°(Rg⋅⋅⋅OC) to 90°. expected at ~400 and ~300 µm are out of range. The CO bond length dependences of IPESs for the complexes have been determined by the In the presence of thermal radiation, BBR induced transition rate Kn'l',nl is given by present analyses. It is possible to assess the accuracy for Ar-CO by comparing experimental data, 1 K = A where transitions in vCO = 0, 1, and 2 states have been observed by IR spectroscopy [3]. The n'l',nl !ω − n'l',nl exp( n'l',nl / kT ) 1 dissociation energies from the zero-point levels, D0, for vCO = 0, 1, and 2, are derived to be 83.099 -1 -1 -1 where An'l',nl is Einstein coefficient [2]. This equation describes the relation between the spontaneous cm , 83.537 cm , and 83.978 cm , respectively. The differences between these D0 values, -1 -1 emission and the stimulated emission. In a case of the far infrared emission around 88 and 113 µm at 0.438cm between vCO = 0 and 1, and 0.879cm between vCO = 0 and 2, correspond to the red room temperature, the value of K14f,13g / A14f,13g and K13g,12f / A13g,12f are ~ 1.91 and ~ 1.33, while the shifts of the origins of the CO vibrational transitions by the complex formation. They are in good value is 3.8 × 10-11 for the near infrared emission at 2 µm. In other words, contribution of BBR to the agreement with the experimentally derived shifts of 0.4377 cm-1 for the fundamental band and state to state transitions can be dominant for optical transitions in the far infrared region. 0.8778 cm-1 for the overtone band. It has been confirmed that the hyperfine splittings observed in the pure rotational transitions of Rg-13C17O [1] are well reproduced for the Ne, Ar, and Kr-CO complexes with the present 3D IPESs.

References [1] T. Ogata, W. Jaeger, I. Ozier, M. C. Gerry, J. Chem. Phys. 98, 9399 (1993). [2] M. Hepp, W. Jaeger, I. Pack, G. Winnewisser, J. Mol. Spectrosc. 176, 58 (1996), M. Hepp, R. Gendriesch, I. Pack, Y. A. Kuritsyn, F. Lewen, G. Winnewisser, M. Brookes, A. R. W. Mckellar, J. K. G. Watson, T. Amano, Mol. Phys. 92, 229 (1997), M. Hepp, R. Gendriesch, I. Pack, F. Lewen, G. Winnewisser, J. Mol. Spectrosc. 183, 295 (1997), V. N. Markov, Y. Xu, W. Jaeger, Rev. Sci. Instrum. 69, 4061 (1998), R. Gendriesch, I. Pack, F. Lewen, L. Surin, D. A. Roth, G. Winnewisser, J. Mol. Spectrosc. 196, 139 (1999), L. A. Surin, B. S. Dumesh, F. Lewen, D. A. Roth, V. P. Kostromin, F. S. Rusin, G. Winnewisser, I. Pack, Rev. Sci. Instrum. 72, 2535 (2001), L.

H. Coudert, I. Pack, L. Surin, J. Chem. Phys. 121, 4691 (2004), D. G. Melnik, S. Gopalakrishnan, T. A. Miller, Fig. 1. (Upper panel) The dispersed emission Fig. 2. Grotrian diagram of Rydberg states of F. C. De Lucia, S. Belov, J. Chem. Phys. 114, 6100 (2001). spectra from the 15p (v15p = 0, N14p = 2, =0) NO. The upward solid arrows indicate the [3] A. R. W. Mckellar, Y. P. Zeng, S. W. Sharpe, C. Wittig, R. A. Beaudet, J. Mol. Spectrosc. 153, 475 (1992), Y. state. (Lower panel) The dispersed emission double-resonant excitation scheme for the Xu, S. Civis, A. R. W. Mckellar, S. Koenig, M. Haverlag, G. Hilpert, M. Havenith, Mol. Phys. 87, 1071 (1996), 2 spectra from 14p (v14p = 0, N14p = 2, =0) state.ℒ excitation from X Π ground state to the 14p and Y. X u , A. R. W. Mckellar, Mol. Phys. 88, 859 (1996), A. R. W. Mckellar, Mol. Phys. 98, 111 (2000), S. Koenig, 15p Rydberg state. The downward solid arrows M. Havenith, Mol. Phys. 91, 265 (1997), I. Scheele, R. Lehnig, M. Havenith, Mol. Phys. 99, 197 (2001), I. References ℒ are transition channels observed in Fig. 1. Scheele, R. Lehnig, M. Havenith, Mol. Phys. 99, 205 (2001), I. Scheele, M. Havenith, Mol. Phys. 101, 1423 [1] Ogi et al., Chem. Phys. Lett. 436, 303 (2007). (2003), M. Havenith, G. Hilpert, M. Petri, W. Urban, Mol. Phys. 81, 1003 (1994), S. Koenig, G. Hilpert, M. [2] Gallagher et al., Appl. Phys. Lett. 34, 369 (1979). Havenith, Mol. Phys. 86, 1233 (1995).

74 7775 A18

Resolving non-adiabatic dynamics of hydrated electrons using ultrafast photoemission anisotropy

Shutaro Karashima and Toshinori Suzuki

Department of chemistry Kyoto University, Kitashirakawa-Oiwakecho, Kyoto,Japan

Hydrated electron is one of the most fundamental chemical species in radiation chemistry. However, its dynamical property and electronical structure are not understood yet [1]. In this study, we performed ultrafast time- and angle-resolved photoemission spectroscopy (TARPES) to elucidate non-adiabatic dynamics of hydrated electron. The 0.1 M aqueous NaBr solution was discharged into a photoelectron spectrometer through a fused silica capillary (15 m in diameter) at a flow rate of 0.2 mL/min. The liquid jet was irradiated with three laser pulses; the 200 nm pulse for creating hydrated electrons in the ground state, and the 700 and 350 nm pulses for pumping to the excited state and probing by photoemission. The polarization direction of the probe pulse was varied with a half wave plate to observe photoemission anisotropy. Photoelectron kinetic energy distribution (PKED) was measured with a time of flight energy analyzer. The cross-correlation between the pump and probe pulses was 50 - 80 fs. Fig. 1a shows time-evolution of PKED. The global fit of PKED provided two decay-associated spectra as shown in Fig. 1b. The 1 component is assigned to photoemission from the first excited state of hydrated electron. The assignment of the 2 component is the key for understanding the non-adiabatic dynamics. To assign this component, we examined the photoemission anisotropy s shown in Fig. 2. The result indicates that low PKE component provides isotropic photoemission, indicating that it is the ground state [2]. Thus, we conclude that internal conversion from the excited to the ground state occurs in 60 fs [3].

Fig.1 (a) PKED vs. time delay Fig.2 PKED measured for different probe polarization (b) The decay associated spectra

Reference [1] D.Borgis, P. J. Rossky, L.Turi, J. Phys. Chem. Lett., 8, 2304 (2017) [2] Y. Yamamoto, Y.Suzuki, et al., Phys. Rev. Lett., 112, 187603 (2014) [3] S.Karashima, Y.Yamamoto, T.Suzuki, Phys. Rev. Lett., 116, 137601 (2016)

7876 A19

Resolving non-adiabatic dynamics of hydrated electrons Roles of biradical intermediates in the photochemical reaction of using ultrafast photoemission anisotropy thiazole: matrix-isolation and theoretical study

Shutaro Karashima and Toshinori Suzuki Jun Miyazakia,b), Hiroshi Takiyamab), and Munetaka Nakatac)

Department of chemistry Kyoto University, Kitashirakawa-Oiwakecho, Kyoto,Japan a)Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3, Kanagawa-machi, Kanazawa, Ishikawa, Japan Hydrated electron is one of the most fundamental chemical species in radiation chemistry. b)Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16, Naka-cho, Koganei, Tokyo, Japan However, its dynamical property and electronical structure are not understood yet [1]. In this study, c) we performed ultrafast time- and angle-resolved photoemission spectroscopy (TARPES) to Graduate School of Bio-Applications and Systems Engineering (BASE), Tokyo University of Agriculture and elucidate non-adiabatic dynamics of hydrated electron. Technology, 2-24-16, Naka-cho, Koganei, Tokyo, Japan The 0.1 M aqueous NaBr solution was discharged into a photoelectron spectrometer through a fused silica capillary (15 m in diameter) at a flow rate of 0.2 mL/min. The liquid jet was irradiated In astrochemical and astrophysical studies, UV photochemistry of heterocyclic compounds gives with three laser pulses; the 200 nm pulse for creating hydrated electrons in the ground state, and the important information on small photofragments composed of H, C, N, O and S, when they are 700 and 350 nm pulses for pumping to the excited state and probing by photoemission. The exposed to the strong UV radiation. In this process, the radical and biradical species including N, S polarization direction of the probe pulse was varied with a half wave plate to observe photoemission and O atoms are playing an important role as photochemical intermediates. Thiazole (1) is one of anisotropy. Photoelectron kinetic energy distribution (PKED) was measured with a time of flight the most famous heterocyclic compounds involving one S and one N atom, implying that thiazole energy analyzer. The cross-correlation between the pump and probe pulses was 50 - 80 fs. has the ability of the precursors of C, N, and S atoms. However, the photochemical reaction of Fig. 1a shows time-evolution of PKED. The global fit of PKED provided two decay-associated thiazole has not been reported except for the photodecomposition by flash photolysis, forming cyano radical and thiocyanate radical [1], while the photochemical reaction from isothiazole (1’) to spectra as shown in Fig. 1b. The 1 component is assigned to photoemission from the first excited thiazole (1) has been reported in various solvents [2]. state of hydrated electron. The assignment of the 2 component is the key for understanding the non-adiabatic dynamics. To assign this component, we examined the photoemission anisotropy s 1 shown in Fig. 2. The result indicates that low PKE component provides isotropic photoemission, 2 5 indicating that it is the ground state [2]. Thus, we conclude that internal conversion from the excited 3 4 to the ground state occurs in 60 fs [3]. (1) (1’)

Fig. 1 Thiazole (1) and Isothiazole (1’)

In order to elucidate the photochemical reactivity and property of thiazole, we have investigated the UV photochemistry of thiazole isolated in a solid argon matrix using FT-IR spectroscopy and DFT calculations [3]. Photoproducts have been identified by comparison of the observed infrared spectra with the corresponding calculated spectral patterns, leading to the conclusions that five kinds of undetected open-chain species, syn-(Z)-2-isocyanoethenethiol, syn- and anti-2-isocyano- ethanethial, 2-isocyanothiirane, and anti-(methyleneamino)-ethenethione, by cleavage of the S1−C2 bond (Path 1), one kind of undetected open-chain species, syn-N-ethynylthioformamide, by cleavage of the S1−C5 bond (Path 2), and the photodecomposition species, HC≡N, HS−C≡CH, S=C=CH2, HC≡CH, HS−C≡N, and S=C=NH, are detectable. In the path 1 and path 2, the formation of the ring-opening biradicals, ·CH=N−CH=CH−S· (Path 1) and ·CH=CH−N=CH−S· (Path 2), are suggested, but not for the formation of ·N=CH−S−CH=CH· (Path 3) by cleavage of N3−C4 bond. In the poster session, we will discuss the stability and reactivity of biradical intermediates in the photochemistry of thiazole isolated in a solid argon matrix.

1 P h a at th P S 2 H C C H Fig.1 (a) PKED vs. time delay Fig.2 PKED measured for different probe polarization N C (b) The decay associated spectra H Path 3 Reference Fig. 2 Three possible ring-opening photoreactions [1] D.Borgis, P. J. Rossky, L.Turi, J. Phys. Chem. Lett., 8, 2304 (2017) References [2] Y. Yamamoto, Y.Suzuki, et al., Phys. Rev. Lett., 112, 187603 (2014) [1] R. Venkatasubramanian, and S. Krishnamachari, Pramana, 30, 529-533 (1989). [3] S.Karashima, Y.Yamamoto, T.Suzuki, Phys. Rev. Lett., 116, 137601 (2016) [2] J. P. Catteau, A. Lablanche-Combier, and A. Pollet, J. Chem. Soc. D, 1018 (1969). [3] J. Miyazaki, H. Takiyama, and M. Nakata, RSC Adv. 7, 4960-4974 (2017).

76 7977 A20

Free Radicals Formed by H Atom Addition to Dimethyl- and Methoxyallene as Determined by Muon Spin Spectroscopy

Myles Scollona), Iain McKenziea),b), Lalangi Chandrasenaa), Mina Mozafaria), and Paul Percivala),b)

a) Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, Canada b) TRIUMF, 4004 Westbrook Mall, Vancouver, Canada

Allyl radicals are important species in combustion and photocatalytic processes. However, the structure and behavior of these radicals has not been fully characterized. Here we present a study of prototypical allyl and vinyl radicals formed by H atom addition to allenes. These are studied by forming the analogous muonium adducts, as muonium (Mu) behaves as a light isotope of hydrogen, and muoniated species can be characterized by muon spin spectroscopy. Two techniques were employed: Transverse Field-Muon Spin Resonance (TF-μSR), and muon Level Crossing Resonance (LCR), which allow for the measurement of muon hfcs and nuclear hfcs, respectively, and thus aid identification of the formed radicals. ESR studies on similar allyl radicals have been reported in the literature. [1-3] Later, Rhodes et al. examined radicals formed by Mu addition to allenes, but muon LCR techniques were undeveloped at the time, so they were unable to determine proton couplings and thus confirm the radical assignments. [4] We report here data for four radicals detected in the muon spin spectra obtained from the two allenes. These correspond to radicals resulting from muonium addition to the carbons at the two and three positions of each compound. They were assigned based on proton hfcs determined from LCR signals, and by comparison to DFT calculations. From the measured hfc temperature dependencies, models are proposed for the vibrational behavior of the four radicals.

Figure 1: Radicals resulting from addition of muonium (hydrogen atom) to allenes.

References [1] J. K. Kochi and P. J. Krusic, J. Am. Chem. Soc., 90, 7155 (1968). [2] J. K. Kochi and P. J. Krusic, J. Am. Chem. Soc., 90, 7157 (1968). [3] P. J. Krusic, P. Meakin, B. E. Smart, J. Am. Chem. Soc., 95, 6211 (1974). [4] C. J. Rhodes, M. C. R. Symons, E. Roduner, and C. A. Scott, Chem. Phys. Lett., 193, 496 (1987).

8078 A21

Free Radicals Formed by H Atom Addition to Dimethyl- and Chiral Effects in Collision Induced Dissociation of Proton Bound Methoxyallene as Determined by Muon Spin Spectroscopy Diastereomeric Complexes of Amino Acids and 1-Phenylethanol

Myles Scollona), Iain McKenziea),b), Lalangi Chandrasenaa), Mina Mozafaria), and Mats Larsson a), Oleksii Rebrov a), Kostiantyn Kulyk a), Mauritz Ryding b), Paul Percivala),b) Richard D. Thomas a), Einar Uggerud b) a) Department of Physics, Stockholm University, SE -106 91 Stockholm, Sweden b) a) Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, Canada Department of Chemistry, University of Oslo, N - 0315 Oslo, Norway b) TRIUMF, 4004 Westbrook Mall, Vancouver, Canada Molecular chirality is a fascinating phenomenon crucial in biochemistry and life. The biomolecular reactions pathway and efficiency can be different depending on the chirality of the Allyl radicals are important species in combustion and photocatalytic processes. However, the molecules involved. The biological homo-chirality challenges the researches to find an answer to structure and behavior of these radicals has not been fully characterized. Here we present a study of the question of its origin as well as a simple and reliable way for enantiomers recognition and prototypical allyl and vinyl radicals formed by H atom addition to allenes. These are studied by separation. Revealing the chiral recognition mechanism on a molecular level can be a key for forming the analogous muonium adducts, as muonium (Mu) behaves as a light isotope of hydrogen, understanding the bio homo-chirality, improvement for existing approaches of enantiomers analysis and muoniated species can be characterized by muon spin spectroscopy. Two techniques were and separation and might shed the light on the origin of life employed: Transverse Field-Muon Spin Resonance (TF-μSR), and muon Level Crossing Resonance (LCR), which allow for the measurement of muon hfcs and nuclear hfcs, respectively, and thus aid We studied chiral ions and their complexes in gas phase by means of mass spectrometry. identification of the formed radicals. ESR studies on similar allyl radicals have been reported in the Experiments with enantiopure amino acids (methionine (Met), phenylalanine (Phe) and tryptophan literature. [1-3] Later, Rhodes et al. examined radicals formed by Mu addition to allenes, but muon LCR (Trp)) in collisions with chiral selectors (2-butanol, 1-phenylethanol) were performed at high and techniques were undeveloped at the time, so they were unable to determine proton couplings and thus low energy (1 keV and 1 eV, respectively)[1, 2]. We could not observe any chiral-dependent confirm the radical assignments. [4] We report here data for four radicals detected in the muon spin fragmentation or complex formation under single collision conditions spectra obtained from the two allenes. These correspond to radicals resulting from muonium addition to the carbons at the two and three positions of each compound. They were assigned based on proton In collision induced dissociation (CID) with argon as target of proton bound diastereomeric hfcs determined from LCR signals, and by comparison to DFT calculations. From the measured hfc complexes of Trp with chiral 2-butanol, we have observed chiral-dependent dissociation [3]. temperature dependencies, models are proposed for the vibrational behavior of the four radicals. Corresponding theoretical calculations have been performed using Gaussian09.

Subsequent and very recent experiments with diastereomeric complexes of Trp, Phe, Met and 1-phenylethanol have been performed. The experiments were performed at 1 eV and lower center-of-mass collision energy. The fragmentation of the complexes was investigated for chiral dependence. Preliminary analysis points to a tendency for the homo-chiral complexes to be less stable against CID.

Our results provide the circumstance of the chiral recognition in CID of proton bound amino acid diastereomeric complexes. These simple systems can serve as models for theoretical calculations, and provide important information about the basic mechanism of chiral recognition.

References [1] K. Kulyk, O. Rebrov, M. H. Stockett, J. D. Alexander, H. Zettergren, H. T. Schmidt, R. D. Thomas, H. Cederquist, and M. Larsson, Int. J. of Mass. Spectrom., 388:59–64 (2015). [2] K. Kulyk, O. Rebrov, M. Ryding, R. D. Thomas, E. Uggerud and M. Larsson, J. Am. Soc. Mass Spectrom. (manuscript, 2017). [3] O. Rebrov, K. Kulyk, M. Ryding, R. D. Thomas, E. Uggerud and M. Larsson, Chirality, 29:3-4, 115–119 (2017).

Figure 1: Radicals resulting from addition of muonium (hydrogen atom) to allenes.

References [1] J. K. Kochi and P. J. Krusic, J. Am. Chem. Soc., 90, 7155 (1968). [2] J. K. Kochi and P. J. Krusic, J. Am. Chem. Soc., 90, 7157 (1968). [3] P. J. Krusic, P. Meakin, B. E. Smart, J. Am. Chem. Soc., 95, 6211 (1974). [4] C. J. Rhodes, M. C. R. Symons, E. Roduner, and C. A. Scott, Chem. Phys. Lett., 193, 496 (1987).

78 8179 A22

1+1' (VUV+UV) threshold ionization application in the study on dynamics of reactive scattering

Wentao Chena,Daofu Yuana, Shengrui Yua,b, Xueming Yangc,a, and Xingan Wanga

a)Deparment of Chemical Physics, University of Science and Technology of China, Jinzhai Road 96, Hefei, China b)Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Gengwen Road 1108, Hangzhou, China c)Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, China

The resonance enhanced multiphoton ionization (REMPI) is one of the most important detection techniques in the study of gas phase reaction dynamics. But the energy resolution of the products are reduced by the electron recoil which occurs after REMPI when the total excitation energy exceeds the ionization limit. The recoil speed can even reach hundreds of meters per second, while detecting the light species, such as H and D atoms. As a result, the image will be blurred dramatically. Recently, a 1+1'(VUV+UV) threshold ionization scheme combined with time sliced velocity map image method was used to detect the H and D atoms in H+HD/D2 and F+HD reactions in our lab. The threshold ionization could reduce the electron recoil. With the help of this method, the rotational state resolved images were obtained. Furthermore, detailed structures in angular distributions were clearly captured.

8280 A23

1+1' (VUV+UV) threshold ionization application in the study on Probing the Conformational Behavior of the C4 Alkyl-Substituted dynamics of reactive scattering Criegee Intermediates by FTMW Spectroscopy

Wentao Chena,Daofu Yuana, Shengrui Yua,b, Xueming Yangc,a, and Xingan Wanga Carlos Cabezas,a J.-C. Guillemin,b and Yasuki Endoa

aDepartment of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., a)Deparment of Chemical Physics, University of Science and Technology of China, Jinzhai Road 96, Hefei, Hsinchu 30010, Taiwan b China Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS - ENSCR, Rennes, France b)Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Gengwen Road 1108, Hangzhou, China Carbonyl oxides (R1R2COO), often called Criegee intermediates (CIs), have been assumed as c) Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, China intermediates generated by the ozonolysis reaction of alkenes, and are thought to play important roles in atmospheric chemistry. After the first laboratory observation of the simplest CI, CH2OO, The resonance enhanced multiphoton ionization (REMPI) is one of the most important detection their experimental characterization has been drastically progressing. Especially alkyl-substituted CIs techniques in the study of gas phase reaction dynamics. But the energy resolution of the products are have attracted much attention since they are more abundant in the atmosphere. Here we report reduced by the electron recoil which occurs after REMPI when the total excitation energy exceeds rotational spectra of alkyl-substituted CIs with four carbon atoms in the structure, named C4 the ionization limit. The recoil speed can even reach hundreds of meters per second, while detecting alkyl-substituted CIs. This group includes methyl-ethyl-ketone oxide or 2-butanone oxide the light species, such as H and D atoms. As a result, the image will be blurred dramatically. Recently, (C2H5CCH3OO) and its structural isomers n-butyraldehyde oxide (C3H7CHOO) and i-butyraldehyde a 1+1'(VUV+UV) threshold ionization scheme combined with time sliced velocity map image method oxide ((CH3)2CHCHOO). These molecules have been produced in the discharge plasma of diiodo alkyl-derivative/O2 gas mixtures, and characterized by Fourier-transform microwave spectroscopy. was used to detect the H and D atoms in H+HD/D2 and F+HD reactions in our lab. The threshold ionization could reduce the electron recoil. With the help of this method, the rotational state resolved For the first of them, C2H5CCH3OO, four different conformers were observed coexisting in the images were obtained. Furthermore, detailed structures in angular distributions were clearly captured. supersonic expansion. The observation of small splittings in the spectra due to the internal rotation of only one methyl group enabled us to determine the barrier heights of the hindered methyl rotation for the four conformers, which have been compared with those reported for other methyl-substituted Criegee intermediates. The relative abundances of the four conformers were explained by taking into account both conformational cooling effects due to collisional relaxation and the entropic effects associated to the flexibility of the molecules. (CH3)2CHCHOO is predicted to have four different conformers in the gas phase, with isopropyl part bonded to syn- or anti- positions with respect to bent COO. Although this investigation is still under way, two conformers have been observed and identified so far. C3H7CHOO is extremely flexible, since it possesses four internal rotation axes that can give rise to conformational isomerism, which result in a high number of low energy conformations. Hence, ab initio calculations predict up to nine different conformers with energy below 1300 cm-1. Preliminary results for this Criegee intermediate are also presented, where we have identified four different species with the aforementioned experimental approach.

Four observed conformers of the methyl-ethyl-substituted Criegee intermediate.

80 8381 A24

Gas-phase autoxidation of cyclohexene as a direct source of organic highly oxidized material

Matti P. Rissanena), Siddharth Iyerb), Xucheng Hea), Mikael Ehna), and Theo Kurténb)

a) Department of Physics, University of Helsinki, P.O. Box 64,00014, Helsinki, Finland b)Department of Chemistry, University of Helsinki, P.O. Box 55, 00014, Helsinki, Finland

Gas-phase oxidation of certain volatile organic compounds (VOC) leads to highly-oxidized very low volatile material that is capable of acting as a direct source of atmospheric secondary organic aerosol (SOA) [1, 2]. Contrary to previous perception of slow oxidation by consecutive reactions in the atmospheric gas mixture, the generation of highly-oxidized multifunctional compounds (HOM) can be tremendously fast. HOM form by pseudo-one-step reactions, even in a sub-second time-scale, by a process called autoxidation [2]. Autoxidation proceeds by sequential peroxy radical (RO2) hydrogen-shift isomerization reactions and subsequent O2 addition steps, until a termination occurs by unimolecular dissociation or by bimolecular reaction [2-4]. Cyclohexene is an endocyclic alkene and a common structural part of many abundant biogenic monoterpenes such as α-pinene and limonene. Its symmetric and relatively simple structure has made it a common surrogate species for tracking detailed oxidation mechanisms and for studying formation of secondary organic material. Previously, we have investigated the autoxidation sequence of cyclohexene leading to gas-phase products with an O/C ratio up to 1.5 [4], and applied the rules generated to understand the autoxidation mechanisms of methylated cyclohexenes [5]. Since then, the relevant autoxidation reaction steps have been updated to include the latest findings on ultrafast hydrogen shifts scrambling the peroxy radical distribution [6], and by further unimolecular dissociation processes. In the current work, cyclohexene autoxidation was perturbed by addition of common atmospheric gas-phase co-reactants NO, NO 2, SO2 and HO2, as well as RO2 derived from other smaller VOCs. These reagents are seen to interfere with the oxidation pathways, mainly terminating autoxidation prematurely and forming products which are indicative of the type of perturbing reaction. We have performed flow reactor investigations of cyclohexene ozonolysis initiated autoxidation under ambient conditions utilizing chemical ionization mass spectrometry (CIMS) with nitrate (NO3-) and iodide (I-) reagent ions to detect products with varying levels of oxidation. By perturbing the reaction mixture with the gas-phase reagents, it is possible to infer mechanistic insight into the important reaction steps that transform a completely volatile precursor molecule into a very low volatile molecule that is able to act as a substrate for atmospheric particle formation.

References [1] Jimenez, J. et al, Science 2009, 326, 1525. [2] Ehn, M. et al. Nature 2014, 506, 476. [3] Crounse, J. D. et al. J. Phys. Chem. Lett. 2013, 4, 3513. [4] Rissanen, M. P. et al. J. Am. Chem. Soc. 2014, 136, 15596. [5] Rissanen, M. P. et al. J. Phys. Chem. A 2015, 119, 4633. [6] Knap, H. C. and Jørgensen, S. J. Phys. Chem. A 2017, 121, 1470.

8498 A25

Gas-phase autoxidation of cyclohexene as a direct source of Quantitative Temperature Dependence of the Microscopic organic highly oxidized material Hydration Structures of Hydrated Phenol Cations

Matti P. Rissanena), Siddharth Iyerb), Xucheng Hea), Mikael Ehna), and Theo Kurténb) Haruki Ishikawa, Itaru Kurusu, Reona Yagi, Ryota Kato, and Yasutoshi Kasahara a) Department of Physics, University of Helsinki, P.O. Box 64,00014, Helsinki, Finland Department of Chemistry, School of Science, Kitasato University, Minami-ku, Sagamihara, Japan b)Department of Chemistry, University of Helsinki, P.O. Box 55, 00014, Helsinki, Finland

Gas phase hydrogen-bonded clusters are treated as simple models of molecules in condensed Gas-phase oxidation of certain volatile organic compounds (VOC) leads to highly-oxidized very phases and studied to reveal microscopic nature of the hydrogen bond. Owing to the development of low volatile material that is capable of acting as a direct source of atmospheric secondary organic IR laser spectroscopic and theoretical techniques, static hydrogen-bond structures of various aerosol (SOA) [1, 2]. Contrary to previous perception of slow oxidation by consecutive reactions in hydrogen-bonded clusters have been determined, so far. For the further understanding of the the atmospheric gas mixture, the generation of highly-oxidized multifunctional compounds (HOM) microscopic nature of hydrogen-bond networks in cluster, their temperature effect is the next issue can be tremendously fast. HOM form by pseudo-one-step reactions, even in a sub-second time-scale, to be investigated. To discuss the temperature effect on microscopic hydration structures in clusters, by a process called autoxidation [2]. Autoxidation proceeds by sequential peroxy radical (RO2) relative populations of the isomers having different hydration structures at well-defined hydrogen-shift isomerization reactions and subsequent O2 addition steps, until a termination occurs temperatures are quite important. In the present study, we measured ultraviolet photodissociation + by unimolecular dissociation or by bimolecular reaction [2-4]. spectra of the temperature-controlled hydrated phenol cation, [PhOH(H2O)5] , trapped in the Cyclohexene is an endocyclic alkene and a common structural part of many abundant 22-pole ion trap [1]. biogenic monoterpenes such as α-pinene and limonene. Its symmetric and relatively simple Experimental and computational details are described elsewhere [1]. We measured the UV + structure has made it a common surrogate species for tracking detailed oxidation mechanisms and photodissociation spectra of [PhOH(H2O)5] in the temperature range from 30 to 150 K. In the for studying formation of secondary organic material. Previously, we have investigated the present study, we observed UV spectra of phenol-trimethylamine cluster cation and analyzed the autoxidation sequence of cyclohexene leading to gas-phase products with an O/C ratio up to 1.5 [4], relative intensities of hotbands of intermolecular vibrational modes. As a result, it was confirmed and applied the rules generated to understand the autoxidation mechanisms of methylated that the temperature of the ions were well-defined in our study. At 30 K, only one isomer (isomer A) cyclohexenes [5]. Since then, the relevant autoxidation reaction steps have been updated to include appears in the spectrum. As the temperature elevates, another isomer (isomer B) appears around 80 the latest findings on ultrafast hydrogen shifts scrambling the peroxy radical distribution [6], and by K. At 150 K, the band intensity of the isomer B is stronger than that of the isomer A. This result further unimolecular dissociation processes. In the current work, cyclohexene autoxidation was indicates a clear temperature-dependence of the relative populations between the isomers A and B. perturbed by addition of common atmospheric gas-phase co-reactants NO, NO 2, SO2 and HO2, as In addition, our quantitative result can be directly compared with the theoretical results. well as RO2 derived from other smaller VOCs. These reagents are seen to interfere with the DFT calculations at B97X-D/6-311++G(3df,3pd) level provided several hydration structures of + oxidation pathways, mainly terminating autoxidation prematurely and forming products which are [PhOH(H2O)5] . The relative populations of these isomers were evaluated statistical mechanically. indicative of the type of perturbing reaction. The behavior observed was quantitatively interpreted by the theoretical estimation. A ring with tail We have performed flow reactor investigations of cyclohexene ozonolysis initiated type hydration motif is dominant in cold condition, whereas a chain-like motif is dominant in hot autoxidation under ambient conditions utilizing chemical ionization mass spectrometry (CIMS) with condition. The temperature dependence of the relative populations among the isomers are well nitrate (NO3-) and iodide (I-) reagent ions to detect products with varying levels of oxidation. By interpreted by the flexibility of the hydration structures, that is, the entropic effect. The present perturbing the reaction mixture with the gas-phase reagents, it is possible to infer mechanistic study provides very quantitative information about the temperature effect on the microscopic insight into the important reaction steps that transform a completely volatile precursor molecule into hydration structures. a very low volatile molecule that is able to act as a substrate for atmospheric particle formation. References References [1] H. Ishikawa et al. J. Phys. Chem. Lett. 8, 2541 (2017). [1] Jimenez, J. et al, Science 2009, 326, 1525. [2] Ehn, M. et al. Nature 2014, 506, 476. [3] Crounse, J. D. et al. J. Phys. Chem. Lett. 2013, 4, 3513. [4] Rissanen, M. P. et al. J. Am. Chem. Soc. 2014, 136, 15596. [5] Rissanen, M. P. et al. J. Phys. Chem. A 2015, 119, 4633. [6] Knap, H. C. and Jørgensen, S. J. Phys. Chem. A 2017, 121, 1470.

98 8583 A26

Near-infrared spectroscopic study of interstellar free radicals

Satoshi Hamanoa), Naoto Kobayashib), Hideyo Kawakitaa), and Keiichi Takenakaa)

a)Laboratory of Infrared High-resolution Spectroscopy (LiH), Kamigamo-Motoyama, Kita-ku, Kyoto, Japan b)Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo, 10762-30, Mitake, Kiso-machi, Kiso-gun, Nagano, Japan

Near-infrared (NIR) high-resolution spectroscopy has become a new tool to investigate the interstellar molecules due to the recent progress of NIR high-resolution spectrographs. There are a plenty of molecular bands in NIR range, such as CO, C2, and CN. In addition, many unidentified molecular bands, diffuse interstellar bands (DIBs), have been found recently in the NIR range. The carriers of DIBs are not revealed yet, but they are considered to originate from the gas-phase carbonaceous molecules, such as fullerenes, polycyclic aromatic hydrocarbons (PAHs). The five NIR DIBs at 0.95 µm were successfully identified as the first electronic transitions of ionized + buckminsterfullerene (C60 ) recently [1]. This was the first identification of DIBs carriers. Due to this finding, NIR spectroscopy of the DIBs becomes more important for studying the distribution + and origins of fullerenes in the interstellar medium and the relations of C60 bands with the unidentified carriers of other anonymous DIBs.

We are conducting the comprehensive survey of DIBs using the NIR high-resolution (R=28,000 or 68,000) spectrograph WINERED, which offers a high sensitivity in the wavelength coverage of 0.91-1.36 micron. In this conference, we will present some results obtained with our survey program of NIR DIBs. We found a number of new NIR DIBs, some of which are detected at the wavelengths close to the peaks of the absorption bands of PAH cations [2]. In addition, the high transmittance of the NIR wavelength range enables us to explore the environmental dependence of the DIBs carriers in the dusty environment and to constrain the properties of DIBs carriers [2,3]. We discuss the properties of DIBs in NIR range and their carriers.

References [1] Campbell E. K., Holz M., Gerlich D., & Maier J. P. Nature, 523, 322 (2015). [2] Hamano S., Kobayashi N., Kondo S., et al., The Astrophysical Journal, 800, 137 (2015) [3] Hamano S., Kobayashi N., Kondo S., et al., The Astrophysical Journal, 821, 42 (2016)

10086 A27

+ Near-infrared spectroscopic study of interstellar free radicals Laboratory Detection of the Linear Carbon Chain HC5N Produced by Top Down Chemistry a) b) a) a) Satoshi Hamano , Naoto Kobayashi , Hideyo Kawakita , and Keiichi Takenaka Mitsunori Araki, Ayane Miyazaki and Koichi Tsukiyama a)Laboratory of Infrared High-resolution Spectroscopy (LiH), Kamigamo-Motoyama, Kita-ku, Kyoto, Japan b) Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo, 10762-30, Mitake, Department of Chemistry, Faculty of Science Division I, Tokyo University of Science, Kiso-machi, Kiso-gun, Nagano, Japan 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan

Near-infrared (NIR) high-resolution spectroscopy has become a new tool to investigate the + After the historic discovery of C60 in a circumstellar envelop [1] and C60 in diffuse clouds [2], the interstellar molecules due to the recent progress of NIR high-resolution spectrographs. There are a new hypothesis, top-down chemistry (TDC), is receiving much attention in the field of plenty of molecular bands in NIR range, such as CO, C2, and CN. In addition, many unidentified astrochemistry [3]. Unlike the ordinary bottom-up chemistry (BUC) in dense clouds which produces molecular bands, diffuse interstellar bands (DIBs), have been found recently in the NIR range. The molecules from atoms and simple molecules by chemical synthesis, TDC produces molecules from carriers of DIBs are not revealed yet, but they are considered to originate from the gas-phase dissociation of large molecules and dust in interstellar space. Large molecules and dust produced in carbonaceous molecules, such as fullerenes, polycyclic aromatic hydrocarbons (PAHs). The five circumstellar envelopes of late-type stars are transported to diffuse clouds and become the starting NIR DIBs at 0.95 µm were successfully identified as the first electronic transitions of ionized + + material of chemistry. The discovery of C60 is a good evidence of the TDC since it is impossible to buckminsterfullerene (C60 ) recently [1]. This was the first identification of DIBs carriers. Due to + produce C60 by BUC in the low-density environment of diffuse clouds. Further proof of the TDC is this finding, NIR spectroscopy of the DIBs becomes more important for studying the distribution + anticipated from laboratory experiments and astronomical observations. and origins of fullerenes in the interstellar medium and the relations of C60 bands with the + Recently, we observed top-down production of a linear carbon chain HC5N from benzonitrile in a unidentified carriers of other anonymous DIBs. hollow-cathode discharge as the first detection in plasmas, although linear carbon chains in a gas-phase have been produced by BUC so far. The obtained rotational profiles were reproduced by We are conducting the comprehensive survey of DIBs using the NIR high-resolution the reported molecular constants [4] at 300 K. The absorption coefficient of the A2Π‒X2Π transition (R=28,000 or 68,000) spectrograph WINERED, which offers a high sensitivity in the + −7 −1 of HC5N was ~1.5×10 cm . The 1~10 ppm of aromatic precursor was thought to be changed to wavelength coverage of 0.91-1.36 micron. In this conference, we will present some results the linear carbon chain. At the very least, this detection suggests a reaction path from an aromatic to obtained with our survey program of NIR DIBs. We found a number of new NIR DIBs, some a linear carbon chain by TDC exists in a gas phase. of which are detected at the wavelengths close to the peaks of the absorption bands of PAH cations [2]. In addition, the high transmittance of the NIR wavelength range enables us to explore the environmental dependence of the DIBs carriers in the dusty environment and to constrain the properties of DIBs carriers [2,3]. We discuss the properties of DIBs in NIR range and their carriers.

References [1] Campbell E. K., Holz M., Gerlich D., & Maier J. P. Nature, 523, 322 (2015). [2] Hamano S., Kobayashi N., Kondo S., et al., The Astrophysical Journal, 800, 137 (2015) [3] Hamano S., Kobayashi N., Kondo S., et al., The Astrophysical Journal, 821, 42 (2016)

2 2 + Figure 1. The A Π-X Π absorption spectra of HC5N + The linear carbon chain HC5N was produced in a hollow cathode by using the precursor gas of (a) benzonitrile or (b) m-tolunitrile in a discharge with a buffer gas of Helium. The spectra were observed by a cavity ringdown spectrometer. References [1] Cami et al., Science, 329, 1180 (2010). [2] Campbell et al., Nature, 523, 322, (2015). [3] Oka and Witt, International Symposium on Molecular Spectroscopy, RH15 (2016). [4] Sinclair et al., J. Chem. Phys., 111, 9600 (1999).

100 8792 A28

Atmospheric oxidation of NH3 by NO3 and OH radicals. Proton coupled electron transfer versus Hydrogen atom transfer reaction mechanisms.

Josep M. Anglada

Departament de Química Biològica i Modelització Molecular, IQAC-CSIC, c/ Jordi Girona, 18 E-08034 Barcelona, Spain e-mail : [email protected]

Ammonia is the most abundant alkaline gaseous species in the troposphere and constitutes the third most abundant nitrogen compound in the atmosphere. It is emitted to the atmosphere from + antropogenic and biogenic sources and the main sinks involve dry and wet deposition forming NH4 contributing to the formation of aerosols. In gas phase ammonia can also be oxidized by OH and NO3 radicals (reactions 1 and 2), which have estimated to contribute to a nonsignificant ~3% to the removal of NH3 in the troposphere

NH3 + OH → NH2 + H2O (1)

NH3 + NO3 → NH2 + HNO3 (2)

Both reaction 1 and 2 involve the abstraction of one hydrogen atom from ammonia by the radical but each reaction takes place in a very different manner. In reaction 1 the hydroxyl radical abstracts one hydrogen atom of NH3 by an hydrogen atom transfer mechanism (hat), which involves a concerted breaking and making of covalent bonds (see Figure 1a). However, reaction 2 takes place through a proton coupled electron transfer process (pcet) in which one electron is transferred from the lone pair of NH3 to the NO3 radical and, simultaneously, one proton is transferred between both moieties (see Figure 1b). The different reaction mechanisms, the computed rate constants and the effect of water vapor on reactions 1 and 2 will be discussed.

Fig. 1a: hat Fig. 1b: pcet

Figure 1: Electronic features for the oxidation of NH3 by OH through an hydrogen atom transfer mechanism (fig 1a), and for the oxidation of NH3 by NO3 through a proton coupled electron transfer mechanism (fig 1b).

References [1] M.A.H. Khan, R.G. Derwent, K. Lyons, J.M. Anglada, J.S. Francisco, C.J. Percival, D.E. Shallcross. Submitted for publication [2] S. Olivella, J. M. Anglada, A. Solé, J. M. Bofill. Chem. Eur. J., 2004, 10, 3404. [3] J. M. Anglada, J. Am. Chem. Soc, 2004, 126, 9809. [4] J. González, J. M. Anglada, J. Phys. Chem. A, 2010, 114,9151 J. M. Anglada, S. Olivella, A. Solé ,J. Am. Chem. Soc. 2014, 136, 6834

8886 A29

Atmospheric oxidation of NH3 by NO3 and OH radicals. Proton Far-infrared study of an interstellar molecule, HCOOCH3 coupled electron transfer versus Hydrogen atom transfer by using synchrotron radiation reaction mechanisms. Kaori Kobayashia), Nobukimi Ohashib), Masaharu Fujitake b), Dennis Tokaryk c), and d) Josep M. Anglada Brant E. Billinghurst

a)Department of Physics, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan Departament de Química Biològica i Modelització Molecular, IQAC-CSIC, c/ Jordi Girona, 18 E-08034 b)Kanazawa University, Kakuma, Kanazawa 920-1192, Japan Barcelona, Spain e-mail : [email protected] c) Department of Physics, University of New Brunswick, Fredericton, NB E3B 5A3, Canada d) Canadian Light Source. Inc., University of Saskatchewan, 44 Innovation Boulevard, Saskatoon, Ammonia is the most abundant alkaline gaseous species in the troposphere and constitutes the third Saskatchewan, S7N 2V3, Canada most abundant nitrogen compound in the atmosphere. It is emitted to the atmosphere from + antropogenic and biogenic sources and the main sinks involve dry and wet deposition forming NH4 Methyl formate (HCOOCH3), is an important astrophysical molecule, first observed about 40 contributing to the formation of aerosols. In gas phase ammonia can also be oxidized by OH and NO3 years ago in a giant molecular gas cloud SGR B2 [1]. More than 1000 transitions have been radicals (reactions 1 and 2), which have estimated to contribute to a nonsignificant ~3% to the observed from several astrophysical sources [2] removal of NH3 in the troposphere The spectrum of methyl formate is complicated by the internal rotation of its methyl group, which is of low frequency and thus becomes mixed with its end-over-end rotation. So far, we have NH3 + OH → NH2 + H2O (1) identified pure rotational transitions in the ground, first, and second excited methyl torsional states,

some of which have been detected in Orion KL [3-5]. However, about 80% of our pure rotational NH3 + NO3 → NH2 + HNO3 (2) laboratory spectra remain unassigned. We expect that the third and fourth torsional states, as well as

the COC deformation and the C-O torsional excited states are responsible for some of the Both reaction 1 and 2 involve the abstraction of one hydrogen atom from ammonia by the radical but unassigned transitions. The physical conditions in Orion KL and availability of highly sensitive each reaction takes place in a very different manner. In reaction 1 the hydroxyl radical abstracts one radio telescope greatly increase the probability that these more excited vibrational states can also be hydrogen atom of NH3 by an hydrogen atom transfer mechanism (hat), which involves a concerted observed in astrophysical sources. In laboratory, two new series of transitions have been identified breaking and making of covalent bonds (see Figure 1a). However, reaction 2 takes place through a in the rotational data, and based on intensity, they lie about 300 cm-1 and 450 cm-1 above the ground proton coupled electron transfer process (pcet) in which one electron is transferred from the lone pair state. However, the uncertainty in these energy estimates is large, so the identity of the particular of NH3 to the NO3 radical and, simultaneously, one proton is transferred between both moieties (see vibrational state which accounts for them cannot be conclusively determined. Therefore, infrared Figure 1b). The different reaction mechanisms, the computed rate constants and the effect of water rotation-vibration spectra of methyl formate focusing particularly on the 300-450 cm-1 region, were vapor on reactions 1 and 2 will be discussed. collected in order to match the structures observed in the far-infrared data to those of the new pure rotational transitions. The experiment was performed on the Far-Infrared Beamline of the Canadian Light Source synchrotron. Methyl formate at a pressure of ~2-8 mTorr was admitted into a 2-m-long White cell cooled to 198K. The cell was set to provide 36 transits of the far-infrared synchrotron radiation, for a total path length of 72 m. Spectra were obtained with both a Si:bolometer and Cu:Ge detector at full resolution (0.00096 cm-1). Very dense spectra of the C-O-C deformation and C-O torsional modes were obtained with high signal-to-noise ratio between 300-360 cm-1. To identify the vibrational level associated with the two new series mentioned above, we have calculated the associated energy level positions using the microwave data. We then calculate a-, b- and c-type spectra from the energy levels [6]. By performing a mathematical correlation of the calculated and Fig. 1a: hat Fig. 1b: pcet experimental spectra, we have determined that the two new series are part of an a-type band at about 318 cm-1, assigned as the COC deformation mode. We expect that similar cross-assignment between Figure 1: Electronic features for the oxidation of NH3 by OH through an hydrogen atom transfer mechanism microwave and far-infrared data will allow us to complete analysis of this band, and perhaps of the (fig 1a), and for the oxidation of NH3 by NO3 through a proton coupled electron transfer mechanism (fig 1b). strong nearby spectrum with a strong Q-branch near 332 cm-1.

References [1] R. D. Brown, J. G. Crofts, P. D. Godfrey, F. F. Gardner, B. J. Robinson, & J. B. Whiteoak, Astrophys. J. Lett., 197, L29 (1975). [2] F. J. Lovas, 2009, NIST Recommended Rest Frequencies for Observed Interstellar References Molecular Microwave Transitions, 2009 Revision (Gaithersberg: NIST), [1] M.A.H. Khan, R.G. Derwent, K. Lyons, J.M. Anglada, J.S. Francisco, C.J. Percival, D.E. Shallcross. http://physics.nist.gov/PhysRefData/Micro/Html/contents.html. [3] K. Kobayashi, K. Ogata, S. Tsunekawa, S. Submitted for publication & Takano, Astrophys. J. Lett., 657, L17 (2007). [4] Takano , Y. S akai, S. Kakimoto, M. Sasaki, & K. [2] S. Olivella, J. M. Anglada, A. Solé, J. M. Bofill. Chem. Eur. J., 2004, 10, 3404. S. Kobayashi, Publ. Astron. Soc. Japan, 64, 89 (2012). [5] Y. Sakai, K. Kobayashi. & T. Hirota. Astrophys. J., 803, [3] J. M. Anglada, J. Am. Chem. Soc, 2004, 126, 9809. 97 (2015). [6] M. Tudorie, V. Ilyushin, J. Vander Auwera, O. Pirali, P. Roy & T. R. Huet, J. Chem. Phys. 137, [4] J. González, J. M. Anglada, J. Phys. Chem. A, 2010, 114,9151 064304 (2012). J. M. Anglada, S. Olivella, A. Solé ,J. Am. Chem. Soc. 2014, 136, 6834

86 8987 A30

Photo-induced dynamics of atmospherically important Criegee intermediates*

Michael F. Vansco, Hongwei Li, and Marsha I. Lester

Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323 USA

The photodissociation dynamics of the simplest Criegee intermediate CH2OO in the long wavelength tail region (364 to 417 nm) of the B1A′ – X1A′ spectrum is investigated using velocity map imaging (VMI).1 Following UV excitation, the O 1D products associated with the primary 1 1 H2CO X A1 + O D product channel are detected by 2+1 REMPI as shown in Figure 1. The anisotropic angular distributions of the O 1D images indicate that dissociation occurs faster than the rotational period of CH2OO (ps). The anisotropy implies that the broad oscillatory structure in the long wavelength region of the UV spectrum is due to short-lived resonances associated with the excited B1A′ state that decay by nonadiabatic coupling to repulsive singlet states. The total kinetic energy release distributions show that the available energy is nearly equally partitioned, on average, between product translational energy and internal excitation of the H2CO co-fragments. The anisotropy and energy partitioning are unchanged with excitation wavelength, and consistent with previously reported experimental and theoretical findings of the CH2OO B-X transition moment and 1 1 2,3 dissociation energy to H2CO X A1 + O D products.

Figure 1. Diabatic potential energy surfaces for CH2OO in its ground and excited electronic singlet states along the O-O dissociation coordinate from R. Dawes, B. Jiang and H. Guo, J. Am. Chem. Soc. 137, 50 (2015).

References [1] M. F. Vansco, H. Li and M. I. Lester, J. Chem. Phys. 147, 013907 (2017). [2] J. H. Lehman, H. Li, J. M. Beames and M. I. Lester, J. Chem. Phys. 139, 141103 (2013). [3] H. Li, Y. Fang, J. M. Beames and M. I. Lester, J. Chem. Phys. 142, 214312 (2015).

*This research was supported by the U.S. Department of Energy - Basic Energy Sciences (DE-FG02-87ER13792).

9088 A31

Photo-induced dynamics Comb-referenced sub-Doppler resolution spectroscopy of atmospherically important Criegee intermediates* of the 32 band of phosphine

Michael F. Vansco, Hongwei Li, and Marsha I. Lester Hiroyuki Sasada a,b) and Shoko Okuda a,b)

Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323 USA a)Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan b)JST, ERATO MINOSHIMA Intelligent Optical Synthesizer (IOS) Project, The photodissociation dynamics of the simplest Criegee intermediate CH2OO in the long 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan wavelength tail region (364 to 417 nm) of the B1A′ – X1A′ spectrum is investigated using velocity map imaging (VMI).1 Following UV excitation, the O 1D products associated with the primary 1 1 H2CO X A1 + O D product channel are detected by 2+1 REMPI as shown in Figure 1. The Inversion splitting of phosphine is one of open questions in molecular spectroscopy. Recent anisotropic angular distributions of the O 1D images indicate that dissociation occurs faster than the calculation predicts that the splitting is 300 kHz and 3 MHz in the v2 = 3 and 4 states [1]. These rotational period of CH2OO (ps). The anisotropy implies that the broad oscillatory structure in the values are ready to be observed using a comb-referenced sub-Doppler resolution spectrometer in the long wavelength region of the UV spectrum is due to short-lived resonances associated with the 3.3 μm region developed by our group [2]. Briefly, the spectrometer contains a excited B1A′ state that decay by nonadiabatic coupling to repulsive singlet states. The total kinetic difference-frequency-generation source, an optical frequency comb, and a cavity-enhanced energy release distributions show that the available energy is nearly equally partitioned, on average, absorption cell (CEAC). The spectral resolution of 80 kHz was demonstrated for CH3D using the between product translational energy and internal excitation of the H2CO co-fragments. The CEAC with a wide optical beam and a large effective path length [3]. anisotropy and energy partitioning are unchanged with excitation wavelength, and consistent with previously reported experimental and theoretical findings of the CH2OO B-X transition moment and Figure 1 depicts observed 1 1 2,3 dissociation energy to H2CO X A1 + O D products. saturated absorption spectrum of the Q (J = 3, K = 3) transition in the 3ν2 band of phosphine with wavelength-modulation and 1f detection. Two Lamb dips of the A1 and A2 components are resolved, and the separation is determined (7.27 ± 0.02) MHz. However, the inversion splitting is not resolved so far. The half width at half maximum of about 680 kHz is limited by pressure broadening. This spectrum was recorded using another CEAC with a narrow optical beam and a short effective path length.

We are going to replace the CEAC to reduce the sample Fig. 1, Obserbed A -A splitting of the Q (J = 3, K = 3) transition in pressure and transit-time 1 2 the 3ν2 band of phosphine. A small feature at the middle of the two broadening, and thereby higher lines is not reproducible. Figure 1. Diabatic potential energy surfaces for CH2OO in its ground and excited electronic singlet states along resolution is expected. the O-O dissociation coordinate from R. Dawes, B. Jiang and H. Guo, J. Am. Chem. Soc. 137, 50 (2015).

References [1] C. Sousa-Silva, J. Tennyson, S. N. Yurchenko, J. Chem. Phys. 145, 091102 (2016). References [2] K. Iwakuni, S. Okubo, and H. Sasada, Opt. Express, 21, 14832 (2013). [1] M. F. Vansco, H. Li and M. I. Lester, J. Chem. Phys. 147, 013907 (2017). [3] M. Abe, K. Iwakuni, S. Okubo, H. Sasada, Opt. Lett., 39, 5277 (2014). [2] J. H. Lehman, H. Li, J. M. Beames and M. I. Lester, J. Chem. Phys. 139, 141103 (2013). [3] H. Li, Y. Fang, J. M. Beames and M. I. Lester, J. Chem. Phys. 142, 214312 (2015).

*This research was supported by the U.S. Department of Energy - Basic Energy Sciences (DE-FG02-87ER13792).

88 9189 A32

Combustion Reactions Followed by Photoelectron Photoion Coincidence Spectroscopy: CRF-PEPICO

Bálint Sztáraya), Krisztina Voronova a), and Patrick Hemberger b), Andras Bodib), and David L. Osbornc)

aDepartment of Chemistry, University of the Pacific, Stockton, CA 95211, USA bLaboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland cCombustion Research Facility, Sandia National Laboratories, Livermore, CA 94551, USA

Photoelectron Photoion Coincidence Spectroscopy (PEPICO) holds the promise of a universal, isomer-selective and sensitive analytical technique for time-resolved quantitative analysis of bimolecular chemical reactions. Towards this goal, we have designed and tested a new PEPICO spectrometer, utilizing simultaneous velocity map imaging for both cations and electrons, while also achieving good cation mass resolution through space focusing. With this new instrument, we have also demonstrated a new approach to dramatically increase the dynamic range in PEPICO spectroscopy. Temporal ion deflection coupled with a position-sensitive ion detector enables suppression of the so-called false coincidence background, increasing the dynamic range in the PEPICO TOF mass spectrum by 2–3 orders of magnitude. The ions experience a time-dependent electric deflection field at a well-defined fraction of their time of flight. This deflection defines an m/z- and ionization-time dependent ion impact position for true coincidences, whereas false coincidences appear randomly outside this region and can be efficiently suppressed. When cold argon + clusters are ionized, false coincidence suppression allows us to observe species up to Ar9 , whereas + Ar4 is the largest observable cluster under traditional operation. This advance provides mass-selected photoelectron spectra for fast, high sensitivity quantitative analysis of reacting systems.

The new CRF-PEPICO electron and ion optics are combined with a side-sampled, slow-flow chemical reactor for photolytic initiation of gas-phase chemical reactions, providing a complete prototype spectrometer and reactor interface to carry out time-resolved experiments. Combining dual velocity map imaging with cation space focusing yields tightly focused photoion images for translationally cold neutrals, while offering good mass resolution for thermal samples as well. The flexible optics design incorporates linear electric fields in the ionization region, surrounded by dual curved electric fields for velocity map imaging of ions and electrons. Furthermore, the design allows for a long extraction stage, which makes this the first PEPICO experiment to combine ion imaging with unimolecular dissociation rate constant measurements of cations to detect and account for kinetic shifts. Four examples are shown to illustrate some capabilities of this new design. We recorded the threshold photoelectron spectrum of the propargyl and the iodomethyl radicals. While the former agrees well with a literature threshold photoelectron spectrum, we have succeeded in resolving previously unobserved vibrational structure in the latter. We have also measured the bimolecular rate constant of the CH2I + O2 reaction and observed its product, the smallest Criegee intermediate, CH2OO. Finally, the second dissociative photoionization step of iodocyclohexane ions, the loss of ethylene from the cyclohexyl cation, is slow at threshold, as illustrated by asymmetric threshold photoionization time-of-flight distributions.

References [1] David L. Osborn, Carl C. Hayden, Patrick Hemberger, Andras Bodi, Krisztina Voronova, Bálint Sztáray*, J. Chem. Phys., 145 164202 (2016) [2] Bálint Sztáray*, Krisztina Voronova, Krisztián Torma, Kyle Covert, Andras Bodi, Patrick Hemberger, Thomas Gerber, and David Osborn*, J. Chem. Phys., 147 013944 (2017)

9290 A33

Combustion Reactions Followed by Photoelectron Photoion Lifetime measurements of bound metastable states in atomic Coincidence Spectroscopy: CRF-PEPICO negative anions in DESIREE.

a) b) a) d,e) a) Bálint Sztáraya), Krisztina Voronova a), and Patrick Hemberger b), Andras Bodib), R. D. Thomas , M. Kamińska , K. C. Chartkunchand , H. Hartman , O. M. Hole , a) a) a) a) a) and David L. Osbornc) R. F. Nascimento , M. Blom , M. Björkhage , A. Källberg , M. Larsson , P. Löfgrena), P. Reinheda), S. Roséna), A. Simonssona), S. Mannervika), a) a) c) aDepartment of Chemistry, University of the Pacific, Stockton, CA 95211, USA H. T. Schmidt , H. Cederquist D. Hanstorp bLaboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute, CH-5232 Villigen PSI, a)Department of Physics, Stockholm University, 106 91 Stockholm, Sweden. Switzerland b) c Institute of Physics, Jan Kochanowski University, 25-369 Kielce, Poland Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551, USA c) Department of Physics, Gothenburg University, 412 96 Gothenburg, Sweden d) Material Science and Applied Mathematics, Malmö University, 205 06 Malmö, Sweden e) Photoelectron Photoion Coincidence Spectroscopy (PEPICO) holds the promise of a universal, Lund Observatory, Lund University, 221 00 Lund, Sweden isomer-selective and sensitive analytical technique for time-resolved quantitative analysis of bimolecular chemical reactions. Towards this goal, we have designed and tested a new PEPICO The cryogenic electrostatic ion-storage ring DESIREE (Double ElectroStatic Ion Ring ExpEriment) (Fig. 1) is constructed to allow ion beams of opposite charge to be confined under extreme high spectrometer, utilizing simultaneous velocity map imaging for both cations and electrons, while also 4 -2 achieving good cation mass resolution through space focusing. With this new instrument, we have vacuum (residual gas p=2x10 cm ) and cryogenic (13 K) conditions in separate “rings” and then also demonstrated a new approach to dramatically increase the dynamic range in PEPICO merged over a common straight section, to study collisions at low and well-defined centre-of-mass energies down to 10 meV. [1, 2]. UHV cryogenic conditions allows storage of keV ions for extended spectroscopy. Temporal ion deflection coupled with a position-sensitive ion detector enables 3 suppression of the so-called false coincidence background, increasing the dynamic range in the periods of time, where 1/e ion beam storage lifetimes of 10 s are achieved [2-5] PEPICO TOF mass spectrum by 2–3 orders of magnitude. The ions experience a time-dependent electric deflection field at a well-defined fraction of their time of flight. This deflection defines an m/z- and ionization-time dependent ion impact position for true coincidences, whereas false coincidences appear randomly outside this region and can be efficiently suppressed. When cold argon + clusters are ionized, false coincidence suppression allows us to observe species up to Ar9 , whereas + Ar4 is the largest observable cluster under traditional operation. This advance provides mass-selected photoelectron spectra for fast, high sensitivity quantitative analysis of reacting systems.

The new CRF-PEPICO electron and ion optics are combined with a side-sampled, slow-flow chemical reactor for photolytic initiation of gas-phase chemical reactions, providing a complete prototype Figure 1: DESIREE ion optics schematic Figure 2: Level structure for 32S- spectrometer and reactor interface to carry out time-resolved experiments. Combining dual velocity map imaging with cation space focusing yields tightly focused photoion images for translationally Atomic anions are unique quantum systems. Due to the absence of a long range 1/r potential there cold neutrals, while offering good mass resolution for thermal samples as well. The flexible optics are only one/a few bound quantum states with typical binding energies below a few eV. Direct design incorporates linear electric fields in the ionization region, surrounded by dual curved electric interactions between the electrons (so called electron correlation) play more important roles than in fields for velocity map imaging of ions and electrons. Furthermore, the design allows for a long cations or neutral systems. This sensitivity makes measurements of long lifetimes in anions extraction stage, which makes this the first PEPICO experiment to combine ion imaging with important bench-markers for many-body treatments of electronic interactions in atom systems [6]. unimolecular dissociation rate constant measurements of cations to detect and account for kinetic shifts. Four examples are shown to illustrate some capabilities of this new design. We recorded the This poster reports on the measurements of the lifetime of excited metastable states in Si-, Ge-, and threshold photoelectron spectrum of the propargyl and the iodomethyl radicals. While the former Sn- performed in one of DESIREE’s storage rings. The E1-forbidden (same parity) transitions have agrees well with a literature threshold photoelectron spectrum, we have succeeded in resolving lifetimes of seconds to hours, and a laser-probing technique is used to selectively detach a small previously unobserved vibrational structure in the latter. We have also measured the bimolecular rate fraction of the ground and/or excited states (illustrated in Fig 2. for 32S- [3]) and the neutrals constant of the CH2I + O2 reaction and observed its product, the smallest Criegee intermediate, produced monitored by an MCP-based detector. Preliminary results are presented and the limitations CH2OO. Finally, the second dissociative photoionization step of iodocyclohexane ions, the loss of of the applied method are addressed. ethylene from the cyclohexyl cation, is slow at threshold, as illustrated by asymmetric threshold photoionization time-of-flight distributions. References [1] R. D. Thomas et al., Rev. Sci. Instrum. 82, 065112 (2011). References [2] H. T. Schmidt et al., Rev. Sci. Instrum. 83, 055115 (2013). [1] David L. Osborn, Carl C. Hayden, Patrick Hemberger, Andras Bodi, Krisztina Voronova, Bálint [3] E. Bäckström et al., Phys. Rev. Lett. 114, 143003 (2015) [4] M. Kaminska et al., Phys. Rev. A , 012512 (2016) Sztáray*, J. Chem. Phys., 145 164202 (2016) 93 [5] K. C. Chartkunchand et al., Phys. Rev. A 92, 032501 (2016) [2] Bálint Sztáray*, Krisztina Voronova, Krisztián Torma, Kyle Covert, Andras Bodi, Patrick Hemberger, [6] D. J. Pegg, Rep. Prog. Phys. 67,857 (2004) Thomas Gerber, and David Osborn*, J. Chem. Phys., 147 013944 (2017)

90 9391

Poster Session B

29 August 19:30 – 22:30

9593 B01 Dissociation Dynamics and Particle Impacts: Electrostatic Ion Beam Traps and Charge Detection Mass Spectrometry R. E. Continetti

B02* Theoretical study on the non-statistical F1/F2 rotational fine structure level distribution in the A-band ICN photodissociation T. Kashimura, T. Ikezaki, Y. Ohta, and S. Yabushita

B03 Ultrafast photodissociation of nitromethane and subsequent reactions of dissociative fragments S. Adachi, H. Kohguchi, and T. Suzuki

B04* A new terahertz emission spectrometer at RIKEN Y. Chiba, N. Sakai, Y. Ebisawa, K. Yoshida, T. Sakai, Y. Watanabe, and S. Yamamoto

B05 Precise determination of the carbon and nitrogen isotopic ratios of HC3N in the massive star-forming region Sgr B2(M) T. Oyama, R. Abe, A. Miyazaki, M. Araki, S. Takano, N. Kuze, Y. Sumiyoshi, and K. Tsukiyama

B06* Role of through bond and through space interactions in stability of dehydro-diazines: A case study of 3c-5e configuration radicals M. Saraswat and S. Venkataramani

B07 Internal and translational energy partitioning of the NO product in the S2 photodissociation of methyl nitrite M. Sumida, S. Masumoto, M. Kato, K. Yamasaki, and H. Kohguchi

B08* Spectroscopic characterization of the reaction products between Criegee intermediates and trace atmospheric gases C. Cabezas and Y. Endo

B09 Low pressure yields of stabilized Criegee intermediates produced from ozonolysis of trans-2-butene and 2,3-dimethyl-2-butene J. Zhang and M. Campos-Pineda

B10* Computational Investigation of RO2 + HO2 Reactions from First-Generation Peroxy Radicals Formed by the Oxidation of Selected Monoterpenes S. Iyer, H. Reiman, K. H. Møller, H. Kjaergaard, and T. Kurtén

B11 Structure-dependent reactivity and spectroscopy of Criegee Intermediates J. J. Lin and Y.-P. Chang

B12* O-atom scattering at the vacuum-liquid interface: The effect of cation fluorination on the surface structure of ionic-liquid mixtures S. M. Purcell, L. D’Andrea, J. M. Slattery, D. W. Bruce, E. J. Smoll Jr., T. K. Minton, M. L. Costen, and K. G. McKendrick

96 B01 Dissociation Dynamics and Particle Impacts: Electrostatic Ion Beam Traps B13 Energy dependence of the Fermi contact interaction constants of nitrogen and Charge Detection Mass Spectrometry dioxide in excited electronic state R. E. Continetti K. Tada, M. Hirata, and S. Kasahara

B02* Theoretical study on the non-statistical F1/F2 rotational fine structure level B14* Infrared absorption spectra of partially deuterated methoxy radicals CH2DO distribution in the A-band ICN photodissociation and CHD2O isolated in solid para-hydrogen T. Kashimura, T. Ikezaki, Y. Ohta, and S. Yabushita K. A. Haupa, B. A. Johnson, E. L. Sibert III, and Y.-P. Lee

~ B03 Ultrafast photodissociation of nitromethane and subsequent reactions of 2 + B15 Isomerization reaction of the MgNC/MgCN X  system dissociative fragments M. Fukushima and T. Ishiwata S. Adachi, H. Kohguchi, and T. Suzuki

B16* Analysis of spectral lineshape of a-X simultaneous collision-induced B04* A new terahertz emission spectrometer at RIKEN absorption by two oxygen molecules Y. Chiba, N. Sakai, Y. Ebisawa, K. Yoshida, T. Sakai, Y. Watanabe, and S. Yamamoto W. Kashihara, A. Syoji, and A. Kawai

B05 Precise determination of the carbon and nitrogen isotopic ratios of HC N in 3 B17 Real-time imaging-based spectroscopy of nitrogen dimer the massive star-forming region Sgr B2(M) K. Mizuse, H. Sato, H. Ishikawa, and Y. Ohshima T. Oyama, R. Abe, A. Miyazaki, M. Araki, S. Takano, N. Kuze, Y. Sumiyoshi, and K.

Tsukiyama B18* Infrared spectrum and ring opening pathway of the cyclobutyl radical

A. R. Brown, P. R. Franke, and G. E. Douberly B06* Role of through bond and through space interactions in stability of dehydro-diazines: A case study of 3c-5e configuration radicals B19 Fourier transform microwave spectroscopy of H2S-MSH (M=Cu, Ag, and Au) M. Saraswat and S. Venkataramani T. Okabayashi, H. Kubota, J. Shirasaki, and E. Y. Okabayashi

B07 Internal and translational energy partitioning of the NO product in the S2 B20* Detection of the simplest Criegee intermediate CH2OO in the 4 band using a photodissociation of methyl nitrite continuous wave quantum cascade laser and its kinetics with SO2 and NO2 M. Sumida, S. Masumoto, M. Kato, K. Yamasaki, and H. Kohguchi J. Qiu and K. Tonokura

B08* Spectroscopic characterization of the reaction products between Criegee B21 Different formation mechanisms of highly excited halogens following the intermediates and trace atmospheric gases multiphoton photolysis of halomethanes C. Cabezas and Y. Endo B.-C. Chang, Z.-J. Lin, and C.-C. Wu

B09 Low pressure yields of stabilized Criegee intermediates produced from B22* Ultrafast Photoemission Spectroscopy of Liquid Water using Ultrashort 134 ozonolysis of trans-2-butene and 2,3-dimethyl-2-butene nm Pulses J. Zhang and M. Campos-Pineda Y. Yamamoto and T. Suzuki

B10* Computational Investigation of RO2 + HO2 Reactions from First-Generation B23 HO2 yield in the reaction of different peroxy radicals with OH radicals Peroxy Radicals Formed by the Oxidation of Selected Monoterpenes C. Fittschen, E. Assaf, and C. Schoemacker S. Iyer, H. Reiman, K. H. Møller, H. Kjaergaard, and T. Kurtén

B24* Development of a novel method for determination of a ratio between HO2 B11 Structure-dependent reactivity and spectroscopy of Criegee Intermediates and RO2 generation paths in HOx cycle J. J. Lin and Y.-P. Chang N. Kohno, K. Ito, Y. Sakamoto, and Y. Kaji

B12* O-atom scattering at the vacuum-liquid interface: The effect of cation B25 Direct measurement of HOX (OH and HO2) radical uptake onto aerosols by a fluorination on the surface structure of ionic-liquid mixtures laser photolysis generation and probe techniques S. M. Purcell, L. D’Andrea, J. M. Slattery, D. W. Bruce, E. J. Smoll Jr., T. K. Minton, M. L. Y. Sakamoto, M. Nakagawa, N. Kohno, J. Hirokawa, and Y. Kajii Costen, and K. G. McKendrick

97 B26 Laser photodissociation spectroscopy of protonated N-aromatic ions: A. J. Trevitt, S. J. Blanksby, C. S. Hansen, J. P. Bezzina, and B. McKinnon

B27 Theoretical study on the substituent effect in Criegee Intermediate reactions K. Takahashi and C. Yin

B28 Diffuse interstellar bands; 100-years-old mystery beginning to be solved? T. Oka

B29 Sub-Doppler molecular spectroscopy with a frequency comb referenced optical parametric oscillator L. Halonen, J. Karhu, M. Vainio, and M. Metsälä

B30 Rotationally-resolved high-resolution laser spectroscopy of S1-S0 transition of fluorene S. Kasahara and S. Kuroda

B31 Isomer-specific detection in the UV photodissociation of the propargyl radical by chirped-pulse mm-Wave spectroscopy in a pulsed quasi-uniform flow B. M. Broderick, N. Dias, N. Suas-David, and A. G. Suits

 B32 Full observation of cascaded radiationless transitions from S2( ) state of pyrazine by ultrafast VUV photoelectron imaging T. Horio and T. Suzuki

*Poster Award Candidates

98 B01

B26 Laser photodissociation spectroscopy of protonated N-aromatic ions: Dissociation Dynamics and Particle Impacts: Electrostatic Ion A. J. Trevitt, S. J. Blanksby, C. S. Hansen, J. P. Bezzina, and B. McKinnon Beam Traps and Charge Detection Mass Spectrometry

B27 Theoretical study on the substituent effect in Criegee Intermediate reactions Robert E. Continetti K. Takahashi and C. Yin Department of Chemistry and Biochemistry, University of California, San Diego 9500 Gilman Drive, La Jolla B28 Diffuse interstellar bands; 100-years-old mystery beginning to be solved? CA 92093-0340 T. Oka

B29 Sub-Doppler molecular spectroscopy with a frequency comb referenced The study of the energetics and dynamics of transient species using negative ion precursors in optical parametric oscillator conjunction with photoelectron-photofragment coincidence spectroscopy has been benefitted from L. Halonen, J. Karhu, M. Vainio, and M. Metsälä the introduction of electrostatic ion beam traps and cryogenic RF accumulator traps in recent years. Recent progress in the examination of transient species, including characterization of the N2O2¯ B30 Rotationally-resolved high-resolution laser spectroscopy of S1-S0 molecular anion and the examination of the OH + CH4 → H2O + CH3 potential energy surface by transition of fluorene photodetachment of OH¯(CH4) will be reviewed. S. Kasahara and S. Kuroda The status of an instrument development project involving a single-particle dust accelerator/decelerator, the Aerosol Impact Spectrometer, will also be reviewed.1 This apparatus B31 Isomer-specific detection in the UV photodissociation of the propargyl makes use of electrospray ionization to produce charged nanoparticles, with the mass and charge of radical by chirped-pulse mm-Wave spectroscopy in a pulsed quasi-uniform single nanoparticles measured using charge detection mass spectrometry techniques prior to flow acceleration or deceleration to desired final velocities for surface impact studies. Applications to B. M. Broderick, N. Dias, N. Suas-David, and A. G. Suits measurements of the coefficient of restitution for polystyrene latex spheres and tin nanoparticles, as well as measurements of the durability of free-standing nanostructure with respect to particle impact,  will be presented. B32 Full observation of cascaded radiationless transitions from S2( ) state of pyrazine by ultrafast VUV photoelectron imaging Acknowledgments: This work has been supported by the U.S. Department of Energy, Office of T. Horio and T. Suzuki Science, Office of Basic Energy Sciences under award number DE-FG03-98ER14879, the NSF-MRI Program grant CHE-129690 and Cymer, an ASML Company.

*Poster Award Candidates References [1] B.D. Adamson, M.E.C. Miller and R.E. Continetti, EPJ Tech. and Instrum. 4:2 (2017) doi: 10.1140/epjti/s40485-017-0037-6

12999 B02

Theoretical study on the non-statistical F1/F2 rotational fine structure level distribution in the A-band ICN photodissociation

Tatsuhiko Kashimuraa), Tomoya Ikezakia), Yusuke Ohta a), and Satoshi Yabushitaa)

a) Graduate School of Science and Technology, Keio University, Japan, Kanagawa, Yokohama

1. Introduction It is well-known that the A-band photodissociation of ICN yields the CN photofragments whose rotational distribution critically depends on the channels.

2 2 + I( 𝑃𝑃𝑃𝑃3/2 ) + CN( Σ ), high 𝑁𝑁𝑁𝑁 Each rotation level N of the∗ CN2 fragments 2is +split into the F1=N+1/2 and ICN + ℎ𝜈𝜈𝜈𝜈 → 1/2 F2=N-1/2 levels. An interestingI ( 𝑃𝑃𝑃𝑃 earlier) + CN observation( Σ ), lowwas 𝑁𝑁𝑁𝑁non-statistical [1] F1/F2 populations. Zare et al. represented the degree of this non-statistical population with the following parameter f(N),

Fig.1 [1] and plotted it as a function of the excitation wavelength λ and N (Fig 1). ( ) [ ( 1) ( 2)][⁄ ( 1) ( 2)] Here, P(F1) and𝑓𝑓𝑓𝑓 P𝑁𝑁𝑁𝑁(F2=) are𝑃𝑃𝑃𝑃 the𝐹𝐹𝐹𝐹 ir− populations 𝑃𝑃𝑃𝑃 𝐹𝐹𝐹𝐹 𝑃𝑃𝑃𝑃. It𝐹𝐹𝐹𝐹 is +clear 𝑃𝑃𝑃𝑃 𝐹𝐹𝐹𝐹 that f(N) depends critically on the𝑓𝑓𝑓𝑓 λ( 𝑁𝑁𝑁𝑁and) N. In this work, we attempt to find the origin of this long-standing problem.

2. Models and Discussions In photodissociation of various diatomic molecules, similar oscillations have been observed in the product angular momentum polarization [2], [3]. Their oscillation is caused by quantum interference between dissociative wavepackets generated on multiple potential energy surfaces. Therefore, we consider that quantum interference between dissociative wavepackets generated simultaneously on multiple potential energy surfaces of ICN is reflected into the F1/F2 population ratios via a nonadiabatic transition at the asymptotic region. To facilitate the interpretation of the nonadiabatic interaction caused by the CN rotational motion, we employ the dynamical states (DS)[4] which are the eigenstate of the Hamiltonian including the electronic Hamiltonian and the CN rotational part of the nuclear Hamiltonian. Fig.2 Coordinate system and some angular momenta As a model ofdyn the nonadiabaticel 2 transition,2 2 we consider2 the angular orb I−CN momentum recoupling𝐻𝐻𝐻𝐻 = 𝐻𝐻𝐻𝐻 described+ 𝑵𝑵𝑵𝑵 ⁄2𝜇𝜇𝜇𝜇𝑟𝑟𝑟𝑟 schematically+ 𝒍𝒍𝒍𝒍 ⁄2𝑀𝑀𝑀𝑀𝑅𝑅𝑅𝑅 as N+( S+j)→(N+S)+j (see also Fig. 2): in the molecular region, S of CN couples with j of I due to the strong exchange interaction between their radical electrons. At the dissociation limit, S couples with N due to the spin-rotation coupling. Based on group theory and our theoretical calculations, we found the presence of the Rozen-Zener-Demkov (RZD) type nonadiabatic transition between the 3A’DS and 4A’DS at the asymptotic regions. With the semiclassical theory, the analytic formula of f(N ) can be obtained as

Here, t3A’ and t4A’ are the ′transition′ 2 ′amplitude2 ′ s to the′ 3A’ and′ 4A’, respectively. δRZD is the 3A 4A 3A 4A 4A 3A RZD additional phase𝑓𝑓𝑓𝑓 caused(𝑁𝑁𝑁𝑁) = by [2𝑡𝑡𝑡𝑡 the 𝑡𝑡𝑡𝑡nonadiabatic⁄(𝑡𝑡𝑡𝑡 + transition. 𝑡𝑡𝑡𝑡 )] sin( 𝜑𝜑𝜑𝜑φ3A’ and− 𝜑𝜑𝜑𝜑 φ4A’ −are 𝛿𝛿𝛿𝛿 the −phase 𝜋𝜋𝜋𝜋⁄s 2)of. the de-Broglie waves on the 3A’ and 4A’ potential energy surfaces, respectively. We calculate the transition dipole moments and the phase difference by various computational methods.

[1] H. Joswig, et al, Faraday Discuss Chem. Soc. 82, 79(1986). [2] A. G. Suits et al. Chem. Rev. 108, 376 (2008). [3] T. Matsuoka et al. J. Phys. Chem. 119, 9609(2015) [4] H. Nakamura, Phys. Rev. A, 26, 3125(1982).

10082 B03

Theoretical study on the non-statistical F1/F2 rotational fine Ultrafast photodissociation of nitromethane and subsequent structure level distribution in the A-band ICN photodissociation reactions of dissociative fragments

Tatsuhiko Kashimuraa), Tomoya Ikezakia), Yusuke Ohta a), and Satoshi Yabushitaa) Shunsuke Adachia), Hiroshi Kohguchib) and Toshinori Suzukia) a) Graduate School of Science and Technology, Keio University, Japan, Kanagawa, Yokohama a)Department of Chemistry, Graduate School of Science, Kyoto University Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan b) 1. Introduction Department of Chemistry, Graduate School of Science, Hiroshima University It is well-known that the A-band photodissociation of ICN yields the 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan CN photofragments whose rotational distribution critically depends on the channels. The photochemistry of nitromethane (NM, CH3NO2) has been extensively studied by theoretical and experimental approaches, however the dissociation mechanism is not fully understood due to the raveled electronic states. The low-lying excited states of NO2 are energetically open in the main 2 2 + I( 𝑃𝑃𝑃𝑃3/2) + CN( Σ ), high 𝑁𝑁𝑁𝑁 product pathway of CH3 + NO2 of the ultraviolet photochemistry. These product states are Each rotationICN level+ Nℎ𝜈𝜈𝜈𝜈 of→ the∗ CN2 fragments 2is +split into the F1=N+1/2 and adiabatically correlated to the different electronic states in the Franck-Condon region of the parent I ( 𝑃𝑃𝑃𝑃1/2) + CN( Σ ), low 𝑁𝑁𝑁𝑁 F2=N-1/2 levels. An interesting earlier observation was non-statistical molecule, where ultrafast electronic interaction between these potential energy surfaces is expected [1] F1/F2 populations. Zare et al. represented the degree of this to occur prior to the chemical reaction. Identification of the two different time scales of electronic and non-statistical population with the following parameter f(N), nuclear dynamics is a key to understanding of polyatomic photochemistry. NM is one of the most

Fig.1 [1] pertinent molecules to examine the electronic evolution followed by the branching product channels and plotted it as a function of the excitation wavelength λ and N (Fig 1). by time-resolved laser spectroscopy. ( ) [ ( 1) ( 2)]⁄[ ( 1) ( 2)] Here, P(F1) and𝑓𝑓𝑓𝑓 P𝑁𝑁𝑁𝑁(F2=) are𝑃𝑃𝑃𝑃 the𝐹𝐹𝐹𝐹 ir− populations𝑃𝑃𝑃𝑃 𝐹𝐹𝐹𝐹 𝑃𝑃𝑃𝑃. It𝐹𝐹𝐹𝐹 is +clear𝑃𝑃𝑃𝑃 𝐹𝐹𝐹𝐹 that f(N) depends critically on the𝑓𝑓𝑓𝑓 λ( 𝑁𝑁𝑁𝑁and) N. In The photochemical reactions examined by pump-probe photoelectron spectroscopy with 14-eV this work, we attempt to find the origin of this long-standing problem. probe pulses [1] are summarized in Fig. 1. A large fraction of NM excited to the S3 state experiences a sequential S3 → S2 → S1 → S0 internal conversion that completes within ex = 24 ± 10 fs, while 2. Models and Discussions there is a dissociation pathway to form CH3 and NO2(A) fragments with diss 50 fs. A theoretical In photodissociation of various diatomic molecules, similar oscillations have been observed in the quantum yield for the dissociation is 0.24 for the nπ* excitation [2]. Other pathways, eg., [2], [3] product angular momentum polarization . Their oscillation is caused by quantum interference isomerization into methyl nitrite (CH₃ONO), seem much less efficient than the≲ primary dissociation between dissociative wavepackets generated on multiple potential energy surfaces. Therefore, we pathway [2], and in fact they did not manifest themselves in the experimental pump-probe consider that quantum interference between dissociative wavepackets photoelectron spectrum (Fig. 2). About half of the NO2 fragments prepared in the A excited state upon generated simultaneously on multiple potential energy surfaces of ICN photodissociation decays to the ground state very quickly (<100 fs). is reflected into the F1/F2 population ratios via a nonadiabatic transition at the asymptotic region. To facilitate the interpretation of the [1] S. Adachi, T. Horio, and T. Suzuki, Opt. Lett. 37, 2118 (2012). nonadiabatic interaction caused by the CN rotational motion, we employ [2] T. Nelson, J. Bjorgaard, M. Greenfield, C. Bolme, K. Brown, S. McGrane, R. J. Scharff, and S. Tretiak, J. the dynamical states (DS)[4] which are the eigenstate of the Hamiltonian Phys. Chem. A 120, 519–526 (2016). including the electronic Hamiltonian and the CN rotational part of [3] Y. Q. Guo, A. Bhattacharya, and E. R. Bernstein, J. Phys. Chem. A 113, 85 (2009). the nuclear Hamiltonian. Fig.2 Coordinate system and some angular momenta As a model ofdyn the nonadiabaticel 2 transition,2 2 we consider2 the angular orb I−CN momentum recoupling𝐻𝐻𝐻𝐻 = 𝐻𝐻𝐻𝐻 described+ 𝑵𝑵𝑵𝑵 ⁄2𝜇𝜇𝜇𝜇 𝑟𝑟𝑟𝑟schematically+ 𝒍𝒍𝒍𝒍 ⁄2𝑀𝑀𝑀𝑀 𝑅𝑅𝑅𝑅as N+( S+j)→(N+S)+j (see also Fig. 2): in the molecular region, S of CN couples with j of I due to the strong exchange interaction between their radical electrons. At the dissociation limit, S couples with N due to the spin-rotation coupling. Based on group theory and our theoretical calculations, we found the presence of the Rozen-Zener-Demkov (RZD) type nonadiabatic transition between the 3A’DS and 4A’DS at the asymptotic regions. With the semiclassical theory, the analytic formula of f(N) can be obtained as

Here, t3A’ and t4A’ are the ′transition′ 2 ′amplitude2 ′ s to the′ 3A’ and′ 4A’, respectively. δRZD is the 3A 4A 3A 4A 4A 3A RZD additional phase𝑓𝑓𝑓𝑓 caused(𝑁𝑁𝑁𝑁) = by[2 𝑡𝑡𝑡𝑡the nonadiabatic𝑡𝑡𝑡𝑡 ⁄(𝑡𝑡𝑡𝑡 + transition.𝑡𝑡𝑡𝑡 )] sin( 𝜑𝜑𝜑𝜑φ3A’ and− 𝜑𝜑𝜑𝜑 φ4A’ −are𝛿𝛿𝛿𝛿 the −phase𝜋𝜋𝜋𝜋⁄2s) of. the de-Broglie waves on the 3A’ and 4A’ potential energy surfaces, respectively. We calculate the transition dipole moments and the phase difference by various computational methods. Fig. 1. (left) Photodissociation of nitromethane (NM) and [1] H. Joswig, et al, Faraday Discuss Chem. Soc. 82, 79(1986). [2] A. G. Suits et al. Chem. Rev. 108, 376 subsequent reactions. (2008). [3] T. Matsuoka et al. J. Phys. Chem. 119, 9609(2015) [4] H. Nakamura, Phys. Rev. A, 26, 3125(1982). Fig. 2. (right) Experimental pump-probe photoelectron spectrum.

82 10199 B04

A New Terahertz Emission Spectrometer at RIKEN

Y. Chibaa,b), N. Sakaib), Y. Ebisawaa), K. Yoshidaa,b), T. Sakai c), Y. Watanabed), and S. Yamamotoa)

a)Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan b)RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan c)Graduate School of Informatics and Engineering, The University of Electro-Communication, Chofu, Tokyo 182-8585, Japan d)Division of Physics, Faculty of Pure and Applied Sciences, University of Tsukuba, Ten-nodai, Tsukuba, Ibaraki 305-8571, Japan

In interstellar space exists various free radicals because of the low-density and low-temperature condition. Rotational emission lines of free radicals are extensively observed with radio telescopes to investigate physical and chemical structures of target sources. For secure identification of molecules and accurate analyses of Doppler shifts caused by overall/internal motions of the target sources, accurate rest frequencies of molecular transitions are indispensable. Rest frequencies of various molecules have been measured by spectroscopic measurements in the laboratory, and are tabulated in the spectral line catalogs with the aid of extrapolation based on spectroscopic analyses. However, their accuracies are sometimes insufficient for identification of molecules and detailed discussions of the velocity structure of the sources, which causes serious limitation and uncertainty in astrophysical and astrochemical interpretations. Hence, it is important to measure rest frequencies of the transitions used for astronomical observations directly by the laboratory spectroscopy. Such an effort is more and more important in the ALMA era, because even rotational spectral lines of various isotopic species as well as those in vibrationally excited states, which have not been well studied in the laboratory, are readily observed, thanks to high sensitivity of ALMA.

With this in mind, we are constructing a new laboratory THz emission spectrometer at RIKEN. This spectrometer can be used not only for frequency measurement, but also for measurements of reaction intermediates such as free radicals. A block diagram of the spectrometer is shown in Figure 1. We measure the emission of rotational transitions of molecules in the 2 m long glass cell by using the superconducting hot electron bolometer (HEB) mixer, which has been developed for the THz astronomical observations [1]. The HEB mixer is mounted on the ALMA-type cartridge receiver system. The THz emission from the molecule is down-converted to the 1.0-1.6 GHz range, and is frequency-analyzed by the XFFTS spectrometer with the maximum spectral resolution of 15 kHz. We have already finished assembling these components and are planning test measurements. At this moment, the frequency coverage is limited to 0.8-0.9 THz and 1.3-1.5 THz. We will extend it to the lower frequencies by employing the ALMA-type SIS mixer receivers.

Figure 1: The block diagram of the spectrometer at RIKEN References [1] T. Shiino, R. Furuta, T. Soma et al. Japanese Journal of Applied Physics, 54, 2015.

10284 B05

A New Terahertz Emission Spectrometer at RIKEN Precise determination of the carbon and nitrogen isotopic ratios

Y. Chibaa,b), N. Sakaib), Y. Ebisawaa), K. Yoshidaa,b), of HC3N in the massive star-forming region Sgr B2(M) T. Sakai c), Y. Watanabed), and S. Yamamotoa) Takahiro Oyamaa), Rin Abea), Ayane Miyazakia), Mitsunori Arakia), Shuro Takanob), a)Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan b)RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan Nobuhiko Kuzec), Yoshihiro Sumiyoshid), and Koichi Tsukiyamaa) c) Graduate School of Informatics and Engineering, The University of Electro-Communication, Chofu, Tokyo 182-8585, Japan a) d) Department of Chemistry, Tokyo University of Science, 1-3, kagurazaka, shinjuku-ku, Tokyo, Japan. Division of Physics, Faculty of Pure and Applied Sciences, University of Tsukuba, Ten-nodai, Tsukuba, b) Ibaraki 305-8571, Japan Department of Physics, General Studies, College of Engineering, Nihon University, 1 Nakagawara, Tokusada, Tamuramachi, Koriyama, Fukushima, Japan. c) In interstellar space exists various free radicals because of the low-density and low-temperature Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi- condition. Rotational emission lines of free radicals are extensively observed with radio telescopes cho, Chiyoda-ku, Tokyo, Japan. d) to investigate physical and chemical structures of target sources. For secure identification of Division of Pure and Applied Science, Graduate School of Science molecules and accurate analyses of Doppler shifts caused by overall/internal motions of the target and Technology, Gunma University, 4-2 Aramaki, Maebashi, Gunma, Japan. sources, accurate rest frequencies of molecular transitions are indispensable. Rest frequencies of various molecules have been measured by spectroscopic measurements in the laboratory, and are Isotopic ratio is a critical parameter in understanding the galactic chemical evolution. Carbon tabulated in the spectral line catalogs with the aid of extrapolation based on spectroscopic analyses. isotopic ratios of organic molecules reflect their formation mechanisms. In the present study, we However, their accuracies are sometimes insufficient for identification of molecules and detailed discussions of the velocity structure of the sources, which causes serious limitation and uncertainty observed the J = 10–9 and 11–10 transitions of the simplest cyanopolyyne HC3N and its isotopomers in astrophysical and astrochemical interpretations. Hence, it is important to measure rest frequencies of the transitions used for astronomical observations directly by the laboratory spectroscopy. Such in the massive star-forming region Sgr B2(M), the Galactic center region, with the Nobeyama 45 m an effort is more and more important in the ALMA era, because even rotational spectral lines of radio telescope. The column density and the rotational temperature of HC3N were determined to be various isotopic species as well as those in vibrationally excited states, which have not been well 2 13 studied in the laboratory, are readily observed, thanks to high sensitivity of ALMA. cm− and 163 K, respectively. The ratios of the column densities for the C isotopomers ଵହ were derived to be [H13CCCN]:[HC13CCN]:[HCC13CN] = 1:1.03(4):0.99(3), where the rotational With this in mind, we are constructing a new laboratory THz emission spectrometer at RIKEN. ͳǤ͸ൈͳͲ This spectrometer can be used not only for frequency measurement, but also for measurements of temperature was fixed to that of HC3N. The ratios are almost the same, suggesting no isotopic reaction intermediates such as free radicals. A block diagram of the spectrometer is shown in Figure 13 fractionation for the specific carbon atoms in HC3N. Therefore, it is considered that the C isotope 1. We measure the emission of rotational transitions of molecules in the 2 m long glass cell by using the superconducting hot electron bolometer (HEB) mixer, which has been developed for the THz exchange reactions do not contribute to make difference among the column densities of the three 13C astronomical observations [1]. The HEB mixer is mounted on the ALMA-type cartridge receiver system. The THz emission from the molecule is down-converted to the 1.0-1.6 GHz range, and is isotopomers in the relatively warm region of Sgr B2(M). In contrast, the reported ratios in TMC-1 frequency-analyzed by the XFFTS spectrometer with the maximum spectral resolution of 15 kHz. and L1527 are 1:1.0(1):1.4(2)1 and 1:1.01(2):1.35(3)2, respectively, where the errors correspond to We have already finished assembling these components and are planning test measurements. At this moment, the frequency coverage is limited to 0.8-0.9 THz and 1.3-1.5 THz. We will extend it to the one standard deviation, and the errors are probably overestimated in TMC-1. The ratios show higher lower frequencies by employing the ALMA-type SIS mixer receivers. abundances of HCC13CN.

We also observed the rotational transitions in the vibrational excited states of HC3N. The

rotational temperature of 362 K in the 4, 5, 6 and 7 excited states was obviously different from that of the vibrational ground state.

15 14 15 In addition, we measured the integrated intensity of the J = 10−9 transition of HC3 N. The N/ N ratio in Sgr B2(M) was tentatively determined to be ~99, which agrees with that estimated by Adande et al. ( ).3 This ratio is thought to reflect difference of nucleosynthesis processes between

14 15 Figure 1: The block diagram of the spectrometer at RIKEN the Nͳʹ͵Ǥͺ and േN ͵͹Ǥͳatoms. [1] S. Takano, A. Masuda, Y. Hirahara, H. Suzuki, M. Ohishi, S. Ishikawa, N. Kaifu, Y. Kasai, K. Kawaguchi, References and T. L. Wilson, Astron. Astrophys. 329, 1156 (1998). [2] M. Araki, S. Takano, N. Sakai, S. Yamamoto, T. [1] T. Shiino, R. Furuta, T. Soma et al. Japanese Journal of Applied Physics, 54, 2015. Oyama, N. Kuze, and K. Tsukiyama, ApJ 833, 291 (2016). [3] G. R. Adande, and L. M. Ziurys, ApJ 744, 194 (2012).

84 103101 B06

Role of Through Bond and Through Space Interactions in Stability of Dehydro-diazines: A Case Study of 3c-5e Configuration Radicals Mayank Saraswat, Sugumar Venkataramani*

Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, S.A.S. Nagar,

Manauli PO, Punjab 140306, India Free radicals are one of the important reactive intermediates in many biological and chemical processes apart from their roles in polymer, synthetic and atmospheric chemistry. Being part of many biomolecules and drug candidates, the radicals corresponding to heterocyclics are equally vital in many biochemical pathways related to diseases and metabolism.[1,2] Diazines are one of the simplest heterocyclic molecules possessing six member aromatic ring with two nitrogen atoms. Based on the relative position of the two nitrogen atoms, there exists three isomeric species, namely pyridazine (1,2-diazine), pyrimidine (1,3-diazine) and pyrazine (1,4-diazine). Due to the fact that these systems are related to biomolecules, creation of a radical center in such molecules can be used as model systems to explore their structural and reactivity aspects relevant to biochemical pathways.[3,4] In this regard, we explore all the dehydro-diazine radical isomers computationally and experimentally. [Scheme 1]

Scheme 1 Potential interactions between electron lone pairs and radical electron in dehydro-diazines In this contribution, we mainly focus on the electronic structure of all possible diazine radical isomers in order to get the insights into the stability of each radicals. Through quantum chemical calculations, we investigated the mode of interaction (through space, TS and through bond, TB) between radical centre and nitrogen lone pairs. The results so far provide a proof for a major role of nitrogen lone pairs in determining the relative stability of radicals having 3c-5e configuration. Also, we found out that through space interactions (direct interaction) is playing a major role over the through bond (indirect interaction through intervening bonds) interactions. The outcome of the computational studies along with preliminary matrix isolation infrared spectroscopic studies on selected systems will be presented through this contribution.

References:

[1] Anamika Mukhopadhyay, Lilit Jacob, Sugumar Venkataramani, Phys. Chem. Chem. Phys. 2017, 19, 394-407

[2] Chitranjan Sah, Lilit Jacob, Mayank Saraswat, Sugumar Venkataramani, J. Phys. Chem. A (Under revision)

[3] Scott W. Wren, Kristen M. Vogelhuber, John M. Garver, J. Am. Chem. Soc. 2012, 134, 6584-6595

[4] Fabio de A. Ribeiro, Guilherme C. Almeida, Wania Wolff, J. Phys. Chem. C 2014, 118, 25978- 25986

60 104 B07

Role of Through Bond and Through Space Interactions in Internal and translational energy partitioning of the NO product in Stability of Dehydro-diazines: A Case Study of 3c-5e the S2 photodissociation of methyl nitrite Configuration Radicals M. Sumida, S. Masumoto, M. Kato, K. Yamasaki, and H. Kohguchi Mayank Saraswat, Sugumar Venkataramani* Department of Chemistry, Graduate School of Science, Hiroshima University, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, S.A.S. Nagar, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526, Japan Manauli PO, Punjab 140306, India Methyl nitrite (CH3ONO) is one of the most intensively investigated polyatomic molecules in Free radicals are one of the important reactive intermediates in many biological and photodissociation dynamics studies. The first absorption band (S1-S0) in the 300 - 400 nm region chemical processes apart from their roles in polymer, synthetic and atmospheric chemistry. exhibits a partially resolved vibronic structure, whereas the second absorption band (S2-S0) at Being part of many biomolecules and drug candidates, the radicals corresponding to wavelengths shorter than 250 nm is broad and structureless. The different appearances of absorption heterocyclics are equally vital in many biochemical pathways related to diseases and spectra can be explained as being a consequence of the individual nuclear motions on the S1 and S2 [1,2] metabolism. Diazines are one of the simplest heterocyclic molecules possessing six potential energy surfaces (PESs). The S1 reaction mechanism is interpreted as vibrational member aromatic ring with two nitrogen atoms. Based on the relative position of the two predissociation. Dissociation on the S2 PES is considered to be fast and direct because a steep nitrogen atoms, there exists three isomeric species, namely pyridazine (1,2-diazine), down-hill PES structure without a potential hump is found in theoretical calculations.[1] However, pyrimidine (1,3-diazine) and pyrazine (1,4-diazine). Due to the fact that these systems are experimental data for the S2 photodissociation are not as abundant as those for the S1 related to biomolecules, creation of a radical center in such molecules can be used as model photochemistry. systems to explore their structural and reactivity aspects relevant to biochemical The photodissociation dynamics of methyl nitrite at a photolysis wavelength of 213 nm in the [3,4] pathways. In this regard, we explore all the dehydro-diazine radical isomers S2-S0 transition are investigated by resonantly-enhance multiphoton ionization (REMPI) computationally and experimentally. [Scheme 1] spectroscopy and the state-resolved ion-imaging of the NO product.[2] The NO photofragment is produced in the v = 0–3 vibrational states, among which our observations imply that the largest population is in the v = 1 state (Figure). The analysis for the rotational state-distribution of the v = 1 state yields a Gaussian-like distribution with highly rotational excitation. The average rotational energy given to the NO (v = 1) photofragment is evaluated to be ~70 kJ/mol, which corresponds to a fraction of ~18% to the available energy. The results of the state-resolved scattering experiment for the NO (v = 1) fragment show the variation of the anisotropy and the translational energy release Scheme 1 Potential interactions between electron lone pairs and radical electron in dehydro-diazines with respect to the NO rotational excitation. The angular distributions of the higher NO rotational states show smaller anisotropy In this contribution, we mainly focus on the electronic structure of all possible diazine parameters. The observed scattering radical isomers in order to get the insights into the stability of each radicals. Through images of NO indicate a relatively quantum chemical calculations, we investigated the mode of interaction (through space, TS narrow internal energy distribution and through bond, TB) between radical centre and nitrogen lone pairs. The results so far of the CH3O counter-product. The provide a proof for a major role of nitrogen lone pairs in determining the relative stability of kinetic energy release and the NO radicals having 3c-5e configuration. Also, we found out that through space interactions rotational energy are efficiently (direct interaction) is playing a major role over the through bond (indirect interaction interconverted in the available through intervening bonds) interactions. The outcome of the computational studies along energy for the CH3O + NO (v = 1) with preliminary matrix isolation infrared spectroscopic studies on selected systems will be product pathway. Although analysis presented through this contribution. of the rotational state-dependence of the kinetic energy release was only References: performed for a single vibrational [1] Anamika Mukhopadhyay, Lilit Jacob, Sugumar Venkataramani, Phys. Chem. Chem. Phys. 2017, state, these results suggest that a 19, 394-407 strong repulsive force exerted in the CH3O―NO bond on the S2 PES is Figure Observed REMPI spectrum of the NO product in the v [2] Chitranjan Sah, Lilit Jacob, Mayank Saraswat, Sugumar Venkataramani, J. Phys. Chem. A (Under not effective for internal excitation = 0 - 3 states in the CH3ONO + h(213nm) reaction. revision) The lower panel is the expanded spectrum of the NO of the CH3O counter-product. (v = 1) photofragment. [3] Scott W. Wren, Kristen M. Vogelhuber, John M. Garver, J. Am. Chem. Soc. 2012, 134, 6584-6595

[4] Fabio de A. Ribeiro, Guilherme C. Almeida, Wania Wolff, J. Phys. Chem. C 2014, 118, 25978- References 25986 [1] H. U. Suter, U. Bruhlmann, J. R. Huber, Chem. Phys. Lett. 171, 63 (1990). [2] M. Sumida, S. Masumoto, M. Kato, K. Yamasaki, H. Kohguchi, Chem. Phys. Lett. 674, 5813 (2017).

60 105103 B08

Spectroscopic Characterization of the Reaction Products between Criegee Intermediates and Trace Atmospheric Gases

Carlos Cabezas, and Yasuki Endo

Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Hsinchu 30010, Taiwan

Carbonyl oxides (R1R2COO), known also as Criegee intermediates (CIs), are produced in the ozonolysis reactions of alkenes. Nascent CIs are considered to be highly excited, promptly emitting the hydroxyl (OH) radical, the most important oxidant in the troposphere. However, the OH emission from the nascent CIs competes with collisional relaxation, producing stabilized CIs (SCIs). Significant amounts of SCIs are considered to be consumed in the troposphere by the reaction with many trace atmospheric gases. These include SO2, NOx, and water vapor and other trace gases present in the polluted urban atmospheres, such as HCl or HNO3. The simplest CI, CH2OO, and HCl reaction has been investigated by ab initio calculations, and its rate constant has been measured. However, there is not any experimental evidence about the nature of the primary reaction products that can provide valuable information for understanding the detailed reaction mechanism. Herein, we report the first spectroscopic characterization of the reaction products between CH2OO and HCl through Fourier-transform microwave (FTMW) spectroscopy. In our experiment, CH2OO molecules have been generated in the discharged plasma of a CH2I2/O2 mixture, which contains a small amount of HCl enough to react with CH2OO. The resulting products (including CH2OO) were characterized by FTMW spectroscopy. Rotational transitions in the 6-40 GHz frequency range were observed by FTMW spectroscopy together with FTMW-mmW and MW-MW double-resonance techniques. The observed species was identified as chloro-methyl hydroperoxide (CMHP), the product resulting from the addition of HCl on CH2OO. In addition, we have investigated the reaction between the methyl derivative Criegee intermediate, CH3CHOO, with water, which is thought to be one of the most important processes because of the high quantity of water vapor existing in the earth atmosphere. Since CH3CHOO can adopt two different conformers in the gas phase, this study can contribute to a better understanding of the effects of the substituents in the reactivity of carbonyl oxides. Using FTMW spectroscopy the hydrogen-bonded complex between water and the syn conformer of CH3CHOO was detected in the discharged plasma of CH3CHI2/O2/water gas mixture. Isotope experiments using heavy water support that the currently observed complex was produced by the reaction of CH3CHOO with water vapor. Pure rotational transitions of hydroxyethyl hydroperoxide (HEHP), the reaction product from CH3CHOO with water, were observed in the experiment as well. The observed species was identified as the second most stable conformer with the help of quantum chemical calculations.

Energy diagrams for the reaction of CH2OO with HCl(—) and H2O(···)(left) and for the reaction of CH3CHOO with H2O (right). Total energies relative to that of separated molecules are given in parentheses (in kcal/mol).

106104 B09

Spectroscopic Characterization of the Reaction Products Low pressure yields of stabilized Criegee intermediates between Criegee Intermediates and Trace Atmospheric Gases produced from ozonolysis of trans-2-butene and

Carlos Cabezas, and Yasuki Endo 2,3-dimethyl-2-butene

Department of Applied Chemistry, Science Building II, National Chiao Tung University, 1001 Ta-Hsueh Rd., Jingsong Zhang and Mixtli Campos-Pineda Hsinchu 30010, Taiwan Department of Chemistry, University of California, Riverside, California 92521, USA Carbonyl oxides (R1R2COO), known also as Criegee intermediates (CIs), are produced in the ozonolysis reactions of alkenes. Nascent CIs are considered to be highly excited, promptly emitting Ozonolysis is one of the main oxidation pathways of alkenes in the atmosphere, as well as a the hydroxyl (OH) radical, the most important oxidant in the troposphere. However, the OH significant source of secondary organic aerosol (SOA) and hydroxyl and organic radicals. Carbonyl emission from the nascent CIs competes with collisional relaxation, producing stabilized CIs (SCIs). oxides, also known as Criegee intermediates (CIs), are key products in the ozonolysis of alkenes, Significant amounts of SCIs are considered to be consumed in the troposphere by the reaction with being produced with a broad internal energy distribution. While CIs with high internal energy can many trace atmospheric gases. These include SO2, NOx, and water vapor and other trace gases dissociate and produce OH and other organic radicals, CIs with low internal energy (known as present in the polluted urban atmospheres, such as HCl or HNO3. stabilized CIs) react rapidly to form other carbonyl compounds involved in SOA production. In this The simplest CI, CH2OO, and HCl reaction has been investigated by ab initio calculations, and its work, measurements of the yield of stabilized Criegee intermediates (sCIs) from the ozonolysis rate constant has been measured. However, there is not any experimental evidence about the nature reaction of trans-2-butene and 2,3-dimethyl-2-butene were carried out at low pressures using cavity of the primary reaction products that can provide valuable information for understanding the ring-down spectroscopy (CRDS). Determination of the yield of sCIs was performed by chemical detailed reaction mechanism. Herein, we report the first spectroscopic characterization of the titration using SO2. In the case of trans-2-butene, the yield of sCIs was found to decrease with reaction products between CH2OO and HCl through Fourier-transform microwave (FTMW) decreasing pressure and reaches zero at the low pressure limit. For 2,3-dimethyl-2-butene, the sCI spectroscopy. In our experiment, CH2OO molecules have been generated in the discharged plasma yield also decreased with decreasing pressure but reached a minimum of 0.12 at the low pressure of a CH2I2/O2 mixture, which contains a small amount of HCl enough to react with CH2OO. The limit, which corresponds to the nascent fraction of CI formed with internal energy below its resulting products (including CH2OO) were characterized by FTMW spectroscopy. Rotational dissociation energy. transitions in the 6-40 GHz frequency range were observed by FTMW spectroscopy together with FTMW-mmW and MW-MW double-resonance techniques. The observed species was identified as chloro-methyl hydroperoxide (CMHP), the product resulting from the addition of HCl on CH2OO. In addition, we have investigated the reaction between the methyl derivative Criegee intermediate, CH3CHOO, with water, which is thought to be one of the most important processes because of the high quantity of water vapor existing in the earth atmosphere. Since CH3CHOO can adopt two different conformers in the gas phase, this study can contribute to a better understanding of the effects of the substituents in the reactivity of carbonyl oxides. Using FTMW spectroscopy the hydrogen-bonded complex between water and the syn conformer of CH3CHOO was detected in the discharged plasma of CH3CHI2/O2/water gas mixture. Isotope experiments using heavy water support that the currently observed complex was produced by the reaction of CH3CHOO with water vapor. Pure rotational transitions of hydroxyethyl hydroperoxide (HEHP), the reaction product from CH3CHOO with water, were observed in the experiment as well. The observed species was identified as the second most stable conformer with the help of quantum chemical calculations.

Energy diagrams for the reaction of CH2OO with HCl(—) and H2O(···)(left) and for the reaction of CH3CHOO with H2O (right). Total energies relative to that of separated molecules are given in parentheses (in kcal/mol).

104 107105 B10

Computational Investigation of RO2 + HO2 Reactions from First- Generation Peroxy Radicals Formed by the Oxidation of Selected Monoterpenes

Siddharth Iyera), Heidi Reimana), Kristian H. Møllerb), Henrik Kjaergaardb), and Theo Kurténa)

a) Department of Chemistry, University of Helsinki, P.O. Box 55, 00014 Finland b) Department of Chemistry, University of Copenhagen, DK-2100, Copenhagen, Denmark

Peroxy radicals (RO2s) produced from the oxidation of biogenic volatile organic compounds (VOCs) are important in the formation of highly oxygenated multifunctional compounds (HOMs). [1] These HOMs are known to play a critical role in the formation of secondary organic aerosols (SOAs) in the atmosphere. [2] An important mechanism that affects the lifetimes of these RO2s (and subsequently their contribution to HOM formation) is their bimolecular reaction with the HO2 radical. This reaction is mostly thought to be a radical sink process, producing closed-shell hydroperoxides (ROOH). . However, the RO2 + HO2 reaction can also produce alkoxy radical products (RO2 + HO2 => RO + OH + O2), a channel that can become relevant for large peroxy radicals formed from the oxidation of monoterpenes. Reactions that lead to the recycling of radical species in the atmosphere can potentially enhance HOM formation. Additionally, the bimolecular RO2 + HO2 reaction can also be a source of tropospheric ozone (RO2 + HO2 => ROH + O3), potentially an important ozone forming pathway in clean (low NOx, where x=1,2,3) environments. In this work, the thermodynamic favorability of the alkoxy and ozone forming channels for a set of RO2s generated by the oxidation of a set of atmospherically relevant monoterpenes was computationally investigated. The monoterpenes considered in this study are alpha-pinene, beta-pinene, limonene, trans-beta-ocimene, and delta-3- carene (that account for more than 80% of the total monoterpene emission), and the oxidants considered are OH, NO3, and ozone.

References [1] M. P. Rissanen et al., J. Am. Chem. Soc., 136, 15596-15606 (2014). [2] T. F. Mentel et al., Atmos. Chem. Phys., 15, 6745-6765 (2015).

108120 B11

Computational Investigation of RO2 + HO2 Reactions from First- Structure-dependent Reactivity and Spectroscopy of Criegee Generation Peroxy Radicals Formed by the Oxidation of Selected Intermediates Monoterpenes a),b) a) Jim Jr-Min Lin and Yuan-Pin Chang Siddharth Iyera), Heidi Reimana), Kristian H. Møllerb), Henrik Kjaergaardb), and Theo Kurténa) a)Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan b)Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan a) Department of Chemistry, University of Helsinki, P.O. Box 55, 00014 Finland b) Department of Chemistry, University of Copenhagen, DK-2100, Copenhagen, Denmark Ozonolysis of alkenes produces Criegee intermediates, which are highly reactive carbonyl oxides and may oxidize atmospheric trace gases, like SO2 (to form SO3 and subsequently H2SO4), NO2, organic Peroxy radicals (RO2s) produced from the oxidation of biogenic volatile organic compounds (VOCs) and inorganic acids, etc. Recently it was found that the reactions of CH2OO with SO2 and NO2 are are important in the formation of highly oxygenated multifunctional compounds (HOMs). [1] These much faster than previously thought, suggesting that Criegee intermediates may play a more HOMs are known to play a critical role in the formation of secondary organic aerosols (SOAs) in the significant role in atmospheric chemistry, including acid rain and aerosol formation. However, our atmosphere. [2] An important mechanism that affects the lifetimes of these RO2s (and subsequently study demonstrated that most of the atmospheric CH2OO would be consumed very quickly by its their contribution to HOM formation) is their bimolecular reaction with the HO2 radical. This reaction reaction with water dimer under typical tropospheric conditions. Interestingly, the rate of this reaction is mostly thought to be a radical sink process, producing closed-shell hydroperoxides (ROOH). exhibits strong negative temperature dependence. On the other hand, the reactions with water vapour . However, the RO2 + HO2 reaction can also produce alkoxy radical products (RO2 + HO2 => RO + were found to be slow for dialkyl substituted Criegee intermediates, like (CH3)2COO, opening an OH + O2), a channel that can become relevant for large peroxy radicals formed from the oxidation of opportunity for them to react with atmospheric trace gases, like SO2. However, the thermal monoterpenes. Reactions that lead to the recycling of radical species in the atmosphere can potentially decomposition of such type of Criegee intermediates is measured to be fast, fast enough to reduce enhance HOM formation. Additionally, the bimolecular RO2 + HO2 reaction can also be a source of their atmospheric concentrations. Other studies also show that the reactivity of a Criegee intermediate tropospheric ozone (RO2 + HO2 => ROH + O3), potentially an important ozone forming pathway in toward reaction with water vapour and its thermal decomposition depends very strongly on its clean (low NOx, where x=1,2,3) environments. In this work, the thermodynamic favorability of the structure. Thus, its atmospheric fate also depends on structure. Furthermore, new kinetic results of alkoxy and ozone forming channels for a set of RO2s generated by the oxidation of a set of Criegee intermediates using high resolution IR laser spectroscopic probe will be discussed. atmospherically relevant monoterpenes was computationally investigated. The monoterpenes considered in this study are alpha-pinene, beta-pinene, limonene, trans-beta-ocimene, and delta-3- carene (that account for more than 80% of the total monoterpene emission), and the oxidants considered are OH, NO3, and ozone.

Difference absorption spectra (black line) of the CH2I2/O2 (0.01 Torr/4 Torr) photolysis system at 298 K obtained from a series of IR chirped pulses which repeatedly scan through the Q branch of CH2OO ν4 fundamental transition around 1285.9 cm-1. The integrated intensity of the highest peak is plotted as blue circles. The red line is the simulated time profile from a kinetics analysis. The inset shows the absorption signal obtained from the first probe pulse; it covers about 0.4 cm-1 at the high frequency side of the Q branch feature. References

[1] M. P. Rissanen et al., J. Am. Chem. Soc., 136, 15596-15606 (2014). [2] T. F. Mentel et al., Atmos. Chem. Phys., 15, 6745-6765 (2015). References JCP 146, 244302 (2017)

120 109 B12

O-Atom Scattering at the Vacuum-Liquid Interface: The Effect of Cation Fluorination on the Surface Structure of Ionic-Liquid Mixtures

S. M. Purcella), L. D’Andreab), J. M. Slatteryb), D. W. Bruceb), E. J. Smoll Jr.c), T. K. Mintonc), M. L. Costena) and K. G. McKendricka)

a)Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH1 4AS b)Department of Chemistry University of York, Heslington, York YO10 5DD, United Kingdom c)Department of Chemistry and Biochemsitry, Montana State University, Bozeman, Montana 59717, United States

It is well known that the physical properties of room temperature ionic liquids can be tailored by altering the constituent ions, or by mixing with other ionic liquids. Our specific aim here is to understand how the surface structure of ionic-liquid mixtures is affected by mixing normal alkyl and fluoroalkyl components, as part of a wider campaign to establish how gas-liquid interactions can be optimized for surface-specific applications, such as multiphase catalysis. 1 3 Figures 1 a) and b) illustrate our technique : O( P) atoms, generated by laser photolysis of NO2, react with alkyl groups at the ionic liquid-vacuum interface to form OH via hydrogen abstraction from a CH2-sub-unit. The nascent OH recoils back into the gas-phase where it is detected using laser induced fluorescence.

a) b)

Figure 1: a) Illustration of reactive O-atom scattering from an ionic liquid surface. OH is formed via hydrogen abstraction from alkyl groups. b) Schematic of experimental apparatus.

Recent experiments have focused on cation mixtures of 1-alkyl-3-methlyimidazolium ([Cnmim]), and a partially fluorinated cation, [C8mim-F], (where the C8 chain has six perfluorinated carbon atoms) with the common anion bis(trifluoromethylsulfonyl)imide ([NTf2]). It will be shown that for [Cnmim](1-x)[C8mim-F]x[NTf2] mixtures, the presence of the partially fluorinated cation strongly depletes the surface of secondary hydrogens, indicating the fluorinated cation is highly surface active. This suggests that selected cations, anions or possibly solutes containing fluorinated groups can be chosen to preferentially occupy the gas-liquid interface. This empirical experimental interpretation will be explored by molecular dynamics simulations of these ionic liquid mixtures, providing a more complete picture of the vacuum interface.

References [1] M. A. Serrate, B. C. Marshall, E. J. Smoll Jr., S. M. Purcell, M. L. Costen, J. M. Slattery, T. K. Minton, K. G. McKendrick, J. Phys. Chem. C 119 5491 (2015).

110108 B13

O-Atom Scattering at the Vacuum-Liquid Interface: The Effect of Energy dependence of the Fermi contact interaction constants Cation Fluorination on the Surface Structure of Ionic-Liquid of nitrogen dioxide in excited electronic state Mixtures Kohei Tadaa), Michihiro Hiratab), and Shunji Kasaharab) S. M. Purcella), L. D’Andreab), J. M. Slatteryb), D. W. Bruceb), E. J. Smoll Jr.c), T. K. a) Mintonc), M. L. Costena) and K. G. McKendricka) Graduate School of Engineering, Kyoto University, Kyoto 615-8530, Japan. b)Molecular Photoscience Research Center, Kobe University, Kobe 657-8501, Japan. a) Institute of Chemical Sciences, School of Engineering and Physical Sciences, Heriot-Watt University, 2 2 2 Nitrogen dioxide (NO2) has three excited electronic states (A B2, B B1, and C A2) Edinburgh, EH1 4AS 2 b)Department of Chemistry University of York, Heslington, York YO10 5DD, United Kingdom within about 2 eV above the ground X A1 state, and these four electronic states are able to couple c)Department of Chemistry and Biochemsitry, Montana State University, Bozeman, Montana 59717, United mutually by the spin-orbit and/or the Herzberg-Teller type interactions. The Fermi contact 2 States interaction constants (FCICs) of the vibronic states in the A B2 state have been considered to 2 2 indicate the degree of state-mixing of the A B2 state and the X A1 state. Some groups, therefore, It is well known that the physical properties of room temperature ionic liquids can be tailored by have reported these constants of the excited vibronic states in 11200 – 13680 cm-1 and 16850 – altering the constituent ions, or by mixing with other ionic liquids. Our specific aim here is to 21500 cm-1 energy region [1-4], and these constants seem to decrease in magnitude with increasing understand how the surface structure of ionic-liquid mixtures is affected by mixing normal alkyl and the vibronic energy. In this study we determined the FCICs of the excited states in 14500 – 16800 fluoroalkyl components, as part of a wider campaign to establish how gas-liquid interactions can be cm-1 region to investigate the state-mixing based on an energy dependence of these constants. optimized for surface-specific applications, such as multiphase catalysis. We observed hyperfine-resolved high-resolution laser-induced fluorescence spectra of 1 3 -1 Figures 1 a) and b) illustrate our technique : O( P) atoms, generated by laser photolysis of NO2, NO2 for the vibronic bands in 14500 – 16800 cm region. Fig. 1. shows a part of the observed react with alkyl groups at the ionic liquid-vacuum interface to form OH via hydrogen abstraction spectra, displaying an example of the hyperfine structure of the k = 0, N = 1 ← 0 transitions, i.e. from a CH2-sub-unit. The nascent OH recoils back into the gas-phase where it is detected using R(0) transitions. We determined the FCICs of the excited states by analyzing the observed hyperfine laser induced fluorescence. structures of the R(0) transitions. We found that the determined FCICs are intermediate in magnitude between those constants in lower and higher energy region. Therefore, as the overall trend, the FCICs were confirmed to decrease monotonically with increasing the vibronic energy. At a) b) -1 2 around 16300 cm , where the vibrationless C A2 state was reported to lie [5], the FCICs were 2 2 determined to be close to zero; this may be interpreted that the C A2 state couples with the A B2 state by the spin-orbit interaction, as suggested in Ref. 4, to ensmallen the FCICs locally.

Figure 1: a) Illustration of reactive O-atom scattering from an ionic liquid surface. OH is formed via hydrogen abstraction from alkyl groups. b) Schematic of experimental apparatus.

Recent experiments have focused on cation mixtures of 1-alkyl-3-methlyimidazolium ([Cnmim]), and a partially fluorinated cation, [C8mim-F], (where the C8 chain has six perfluorinated carbon atoms) with the common anion bis(trifluoromethylsulfonyl)imide ([NTf2]). It will be shown that for [Cnmim](1-x)[C8mim-F]x[NTf2] mixtures, the presence of the partially fluorinated cation strongly depletes the surface of secondary hydrogens, indicating the fluorinated cation is highly surface active. This suggests that selected cations, anions or possibly solutes containing fluorinated groups can be chosen to preferentially occupy the gas-liquid interface. This empirical experimental -1 interpretation will be explored by molecular dynamics simulations of these ionic liquid mixtures, Fig. 1. An observed hyperfine structure of the R(0) line located at 15435.8 cm and a schematic energy providing a more complete picture of the vacuum interface. diagram in the J-coupling scheme. The signals with asterisks are other hyperfine lines.

References References: [1] G. Persch et al, J. Mol. Spectrosc. 123, 356 (1987). [2] C. A. Biesheuvel et al, Chem. Phys. Lett. [1] M. A. Serrate, B. C. Marshall, E. J. Smoll Jr., S. M. Purcell, M. L. Costen, J. M. Slattery, T. K. Minton, K. G. 269, 515 (1997). [3] C. A. Biesheuvel et al, J. Chem. Phys. 109, 9701 (1998). [4] J. Xin et al, J. Chem. Phys. McKendrick, J. Phys. Chem. C 119 5491 (2015). 115, 8868 (2001). [5] A. Weaver et al, J. Chem. Phys. 90, 2070 (1989).

108 111109 B14

Infrared absorption spectra of partially deuterated methoxy radicals CH2DO and CHD2O isolated in solid para-hydrogen

Karolina A. Haupaa), Britta A. Johnsonb), Edwin L. Sibert IIIb), and Yuan-Pern Leea), c)

a) Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan b) Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, WI 53706, USA c) Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan

Irradiation of a p-H2 matrix containing deuterated d1-nitritomethane (CH2DONO) at 3.3 K with laser light at 355 nm yielded infrared absorption lines associated with the following fundamental vibrational modes at 2116.4/2177.4 (ν1), 1532.5/1351.1 (ν2), 1028.0/1072.0 (ν3), 2898.5/2791.3 (ν4), −1 1337.5/1403.7 (ν5), 1098.6, (609.9)/845.0 (ν6 and ν9), 2962.7/2799.8 (ν7), 1220.0/(1258.2) (ν8) cm that are assigned to the d1-methoxy (CH2DO) radical; the two numbers in each mode correspond to the A' and A" diabats, respectively, the numbers in parentheses indicate predicted vibrational wavenumbers of unobserved fundamentals, and the question mark indicates a tentative assignment. The assignments are based on the photolytic behavior and comparison of observed vibrational wavenumbers and IR intensities with those predicted with a fitted CCSD(T)/cc-pVTZ force field; the average deviation between experiments and fitted theoretical results is 13 ± 14 cm−1. These lines of ‒3 −1 CH2DO diminished after irradiation with a rate coefficient (3.5 ± 1.0) ∙ 10 s ; predominantly c- CHDOH and a small amount of t-CHDOH were produced. Similarly, the vibronic spectrum for the partially deuterated specie d2-methoxy radical (CHD2O) was obtained on irradiation of doubly deuterated d2-nitritomethane (CHD2ONO) at 355 nm. Lines associated with the fundamental vibrational modes were observed and assigned as 2805.5/2943.0 (ν1), 1179.5/1366.2 (ν2), 1128.6/(1099.1) (ν3), 2049.7/(2076.3) (ν4), 1021.8/(1041.9 and 1099.1) (ν5), 1011.5/945.7 (ν6), 2210- −1 2230/(2169.2) (ν7), (1245.6)/1342.1 (ν8), and (765.8)/(556.5) (ν9) cm . The average deviation −1 between the experimental and theoretical states is 21 ± 25 cm . These lines of CH2DO diminished −3 −1 with a rate coefficient (6.0±1.4) ∙ 10 s after irradiation; CD2OH was produced as a major product. Rate coefficients of the decays of CH3O, CH2DO, CHD2O, and CD3O and there corresponding potential energy surfaces are compared.

112110 B15

Infrared absorption spectra of partially deuterated methoxy Isomerization reaction of the MgNC/MgCN system radicals CH2DO and CHD2O isolated in solid para-hydrogen 𝟐𝟐𝟐𝟐𝟐𝟐 Masaru Fukushima and Takashi Ishiwata𝑿𝑿𝑿𝑿̃ 𝚺𝚺𝚺𝚺 a) b) b) a), c) Karolina A. Haupa , Britta A. Johnson , Edwin L. Sibert III , and Yuan-Pern Lee Faculty of Information Sciences, Hiroshima City University, Hiroshima 731-3194, Japan a) Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, We generated MgNC in a supersonic free jet expansions, adopting the laser ablation technique, and Hsinchu 30010, Taiwan have observed the laser induced fluorescence ( LIF ) of the transition. We have b) Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, measured the LIF dispersed fluorescence spectra from single vibronic2 levels (𝟐𝟐𝟐𝟐𝟐𝟐 SVL ) of the Mg-N-C WI 53706, USA bending ( ) mode in the upper state. In our previous work𝐴𝐴𝐴𝐴̃ Π [1],− 𝑋𝑋𝑋𝑋thẽ vibronic𝚺𝚺𝚺𝚺 structures in the c) Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan SVL dispersed spectra were analyzed2 not only according to the usual procedure with molecular 2 constants, 𝜈𝜈𝜈𝜈such as vibrational constants,𝐴𝐴𝐴𝐴̃ Π and [2], but also adopting internal rotation model, Irradiation of a p-H2 matrix containing deuterated d1-nitritomethane (CH2DONO) at 3.3 K with laser which is widely used to analyze internal vibrational modes, such as internal rotation of methyl 2 22 light at 355 nm yielded infrared absorption lines associated with the following fundamental group [3]. The latter analysis correspond𝜔𝜔𝜔𝜔s to that𝑥𝑥𝑥𝑥 the bending structure is analyzed as the level vibrational modes at 2116.4/2177.4 (ν1), 1532.5/1351.1 (ν2), 1028.0/1072.0 (ν3), 2898.5/2791.3 (ν4), structure on the isomerization reaction pathway, MgNC ⇔ MgCN, because the reaction is −1 1337.5/1403.7 (ν5), 1098.6, (609.9)/845.0 (ν6 and ν9), 2962.7/2799.8 (ν7), 1220.0/(1258.2) (ν8) cm interpreted as the internal rotation of the CN moiety beside Mg as a spectator; i.e., as the rotation of that are assigned to the d1-methoxy (CH2DO) radical; the two numbers in each mode correspond to Mg around CN. Although both analyses satisfactorily reproduce the bending vibrational levels the A' and A" diabats, respectively, the numbers in parentheses indicate predicted vibrational observed, the internal rotation model is limited to analyzing only levels with l = 0, since it is just a wavenumbers of unobserved fundamentals, and the question mark indicates a tentative assignment. one-dimensional ( 1D ) model along a round orbit for the rotation. The internal rotation potential ⇔ The assignments are based on the photolytic behavior and comparison of observed vibrational thus obtained indicates the potential surface of the isomerization reaction, MgNC MgCN, but it is just 1D slice of the multi-dimensional isomerization potential. In the present work, we extend the wavenumbers and IR intensities with those predicted with a fitted CCSD(T)/cc-pVTZ force field; the analysis to two dimensions ( 2D ); we expand the vibrational wavefunctions of the bending mode average deviation between experiments and fitted theoretical results is 13 ± 14 cm−1. These lines of by spherical harmonics, and analyze all of the observed bending vibrational levels, i.e., not only the ‒3 −1 2 CH2DO diminished after irradiation with a rate coefficient (3.5 ± 1.0) ∙ 10 s ; predominantly c- l = 0 levels, but also those of l > 0. The present 2D analysis also satisfactorily𝜈𝜈𝜈𝜈 reproduces the CHDOH and a small amount of t-CHDOH were produced. Similarly, the vibronic spectrum for the observed vibrational structure, and the 2D potential surface, which is characterized using two partially deuterated specie d2-methoxy radical (CHD2O) was obtained on irradiation of doubly quantum numbers, and l, and which corresponds to the isomerization reaction potential. deuterated d2-nitritomethane (CHD2ONO) at 355 nm. Lines associated with the fundamental 2 vibrational modes were observed and assigned as 2805.5/2943.0 (ν1), 1179.5/1366.2 (ν2), 𝑣𝑣𝑣𝑣 1128.6/(1099.1) (ν3), 2049.7/(2076.3) (ν4), 1021.8/(1041.9 and 1099.1) (ν5), 1011.5/945.7 (ν6), 2210- −1 2230/(2169.2) (ν7), (1245.6)/1342.1 (ν8), and (765.8)/(556.5) (ν9) cm . The average deviation [1] M. Fukushima and T. Ishiwata, J. Chem. Phys. 135, 124311 (2011). −1 [2] e.g. G. Herzberg, MM III, D. Van Nostrand Company (Canada), LTD. (1967). between the experimental and theoretical states is 21 ± 25 cm . These lines of CH2DO diminished −3 −1 [3] e.g. J. M. Hollas, High Resolution Spectroscopy 2nd ed., John Wiley & Sons, Chichester (1998). with a rate coefficient (6.0±1.4) ∙ 10 s after irradiation; CD2OH was produced as a major product. Rate coefficients of the decays of CH3O, CH2DO, CHD2O, and CD3O and there corresponding potential energy surfaces are compared.

110 113111 B16

Analysis of spectral lineshape of a-X simultaneous collision-induced absorption by two oxygen molecules

Wataru Kashiharaa), Atsushi Syojia), and Akio Kawaia),b)

a)Tokyo Institute of Technology b)Kanagawa University

Oxygen dimol is transiently generated when two oxygen molecules collide. At this short period, the electron clouds of molecules are distorted and some forbidden optical electronic transitions become partially allowed. These transitions are called CIA (Collision-induced absorption). There have been known several CIA bands appearing in the spectral region from UV to near IR with broad spectral lineshape. Absorption of solar radiation by oxygen dimol is a small but significant part of the total budget of incoming shortwave radiation, and understanding of CIA in dimol O2 is of significance. However, a theory predicting the line shape of CIA is still under developing. In this study, we measured the CIA band around 630 nm that has been assigned to optical transition, 1 1 3 − 3 − a ∆g(v=0):a ∆g(v=0)-X Σg (v=0):X Σg (v=0) of oxygen dimol. CRDS(Cavity Ring-down Spectroscopy) was employed to measure this weak absorption CIA band of oxygen. Laser beam around 630 nm was generated by a dye laser that was pumped by a YAG Laser. Multiple reflection of the probe light was performed within a vacuum chamber that was equipped with two high reflective mirrors. We discuss the measured lineshape of CIA on the basis of collision pair model.

㻌 㻌 8

14 -1 Measured values 7 -1 12 Collion-induced absorption cm 㻌㻌Mesured values Parabola fitting -7 6 㻌㻌 cm Fitting

-8 10 Rayleigh scartting 5 8 295K 4 1 atm 㻌 㻌 㻌 6 3 4 2

Light loss / 10 Light loss 2 1

0 Light absorption / 10 0 0 2 4 6 8 10 12 14 15000 15500 16000 16500 17000 -1 18 -3 Wavenumber㻌 / cm nO2 / 10 molecule cm

Fig.1 Light loss at 630 nm against the number density  Fig.2 CIA spectrum around 630 nm

References [1] S. Solomon, R.W. Portmann, R.W. Sanders, J.S. Daniel, J. Geophys. Res., 103 (1998) 3847. [2] M.Sneep, W. Ubachs, J. Quant. Spectrosc. Radiat. Transfer 92 (2005) 293.

114112 B17

Analysis of spectral lineshape of a-X simultaneous Real-time Imaging-based Spectroscopy of Nitrogen Dimer collision-induced absorption by two oxygen molecules a) b) b) a)c) Kenta Mizuse , Hikaru Sato , Haruki Ishikawa , and Yasuhiro Ohshima Wataru Kashiharaa), Atsushi Syojia), and Akio Kawaia),b) a) Tokyo Institute of Technology, 2-12-1-W4-9 Ookayama, Meguro, Tokyo, Japan b) Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, Japan a)Tokyo Institute of Technology c) Institute for Molecular Science, 38 Nishi-Gonaka, Myodaiji, Okazaki, Aichi, Japan b)Kanagawa University

Oxygen dimol is transiently generated when two oxygen molecules collide. At this short period, Intermolecular interaction between nitrogen molecules is of great importance in atmospheric the electron clouds of molecules are distorted and some forbidden optical electronic transitions chemistry. This interaction induces dipole-allowed transitions of nitrogen in the infrared and become partially allowed. These transitions are called CIA (Collision-induced absorption). There far-infrared region, and it affects the radiative energy balance of the Earth. To understand the nature have been known several CIA bands appearing in the spectral region from UV to near IR with broad of such a two-body intermolecular interaction, spectroscopic study on molecular clusters in the gas spectral lineshape. Absorption of solar radiation by oxygen dimol is a small but significant part of phase is one of the powerful approaches. For the nitrogen clusters, however, due to their weak optical transitions between microwave to ultraviolet region, spectroscopic investigations have been the total budget of incoming shortwave radiation, and understanding of CIA in dimol O2 is of significance. However, a theory predicting the line shape of CIA is still under developing. In this rare. Therefore, no direct information on the structure and intermolecular potential has been study, we measured the CIA band around 630 nm that has been assigned to optical transition, obtained. 1 1 3 − 3 − In this study, we developed a new method to probe the structure and dynamics of the a ∆g(v=0):a ∆g(v=0)-X Σg (v=0):X Σg (v=0) of oxygen dimol. 1 CRDS(Cavity Ring-down Spectroscopy) was employed to measure this weak absorption CIA nitrogen dimer by using a time-domain approach. We carried out an impulsive Raman excitation band of oxygen. Laser beam around 630 nm was generated by a dye laser that was pumped by a pump and Coulomb-explosion-imaging probe experiment. Because dipole transitions of the nitrogen YAG Laser. Multiple reflection of the probe light was performed within a vacuum chamber that was dimer would be weak, we focused on the Raman process. Imaging probe gives us instantaneous equipped with two high reflective mirrors. We discuss the measured lineshape of CIA on the basis of structural/spatial information. In the experiment, nitrogen dimer formed in a supersonic jet collision pair model. expansion was irradiated with a linearly polarized Raman pump pulse (820 nm, <1 ps, 0.5 mJ). Subsequent dynamics were probed with a time-delayed, circularly polarized probe pulse (407 nm, + 80 fs, 0.3 mJ). Upon probe irradiation, (N2)2 was doubly ionized, and N2 fragments were ejected + 㻌 due to the Coulomb repulsion. Spatial distribution of the N2 fragments was measured with a 2D 㻌 1 8 spatial-slice ion imaging setup.

14 -1 Measured values 7 Figure 1 shows the -1 12 Collion-induced absorption cm 㻌㻌Mesured values -7 time-dependent orientation function of the Parabola fitting 6 㻌㻌 cm Fitting

-8 10 Rayleigh scartting 5 nitrogen dimer obtained from the observed 295K + 8 real-time N2 ion image. When the 4 1 atm 㻌 㻌 㻌 intermolecular axis of the dimer is oriented 6 3 along the pump pulse polarization, the value 4 2 of this function becomes larger. Therefore, Light loss / 10 Light loss 2 1 the time trace corresponds to the Figure 1. Time trace of the orientation function 0 Light absorption / 10 0 2 + time-domain rotational spectroscopic data. , where  is the ejected angle of the N2 ions 0 2 4 6 8 10 12 14 15000 15500 16000 16500 17000 with respect to the pump polarization. -1 In this trace, revival structures with a ~230 18 -3 Wavenumber㻌 / cm nO2 / 10 molecule cm ps period can be seen. To obtain spectral information from this periodic trace, we carried out   Fig.1 Light loss at 630 nm against the number density Fig.2 CIA spectrum around 630 nm Fourier transformation (Figure 2). In the FT spectrum, several series of equally spaced peaks can be seen. Spacing between peaks (~4.4 GHz) agrees References with the observed 230 ps period. The main series [1] S. Solomon, R.W. Portmann, R.W. Sanders, J.S. Daniel, J. Geophys. Res., 103 (1998) 3847. indicated by a solid line corresponds to the energy [2] M.Sneep, W. Ubachs, J. Quant. Spectrosc. Radiat. Transfer 92 (2005) 293. difference of the J = 2 Raman transition in the lowest state for the almost free-internal rotation of 2 the N2 units. From the observed data, we Figure 2. Fourier transform of (t). determined a rotational constant (2.19 GHz), a (inset) Schematic of (N2)2 structure and the centrifugal distortion (1.7 MHz), and intermolecular determined intermolecular distance. distance (4.05 Å) for the first time. Other series can be assigned on the basis of nuclear spin statistics (isomers) and Coriolis coupling. Details of our new experimental setup and analyses of spectral data will be presented. References [1] K. Mizuse, K. Kitano, H. Hasegawa, Y. Ohshima, Sci. Adv. 1, e1400185 (2015).

112 115113 B18

Infrared Spectrum and Ring Opening Pathway of the Cyclobutyl Radical

Alaina R. Brown(a), Peter R. Franke(a), Gary E. Douberly(a)

(a)University of Georgia, 140 Cedar St., Athens, GA, USA

Helium nanodroplet isolation (HENDI) is used to probe the infrared spectrum of cyclobutyl radical (∙C4H7), formed from the pyrolysis of cyclobutylmethyl nitrite (C4H7(CH2)ONO). Rotational fine structure is partially resolved for five bands in the CH stretching region. A hybrid CCSD(T) force field with quadratic (cubic and quartic) force constants was computed with the ANO1 (ANO0) basis set. These results were used to simulate anharmonic frequencies in the 2800- 3100 cm-1 region by VPT2+K simulations. Three bands in this region are purely harmonic in nature while the remainder derive intensity from highly coupled anharmonic states corresponding to CH2 bend overtones and combinations. As proposed by Schultz and co-workers,1 upon cyclobutyl ring opening, the 1-methylallyl radical is formed as well as 1,3-butadiene, given a sufficient pyrolysis temperature. Evidence of allylcarbinyl radical, another intermediate proposed along this path, is not observed.

References [1] J.C. Schultz, F.A. Houle, J.L. Beauchamp, J. Am. Chem. Soc. 106, 7336 (1984).

116114 B19

Infrared Spectrum and Ring Opening Pathway of the Fourier Transform Microwave Spectroscopy Cyclobutyl Radical of H2S-MSH (M=Cu, Ag, and Au)

Alaina R. Brown(a), Peter R. Franke(a), Gary E. Douberly(a) Toshiaki Okabayashi, Hirofumi Kubota, Junpei Shirasaki, and Emi Y. Okabayashi

(a)University of Georgia, 140 Cedar St., Athens, GA, USA Shizuoka University, Faculty of Science, Department of Chemistry, Oya 836, Shizuoka 422-8529, Japan

Helium nanodroplet isolation (HENDI) is used to probe the infrared spectrum of Gold is one of the least reactive elements, which has been used as coinage and jewelry since cyclobutyl radical (∙C4H7), formed from the pyrolysis of cyclobutylmethyl nitrite (C4H7(CH2)ONO). ancient times. However, about 25 years ago, it was found that gold nanoclusters exhibit excellent Rotational fine structure is partially resolved for five bands in the CH stretching region. A hybrid catalytic activity and selectivity [1], so these have attracted much attention as promising catalysts so CCSD(T) force field with quadratic (cubic and quartic) force constants was computed with the far.. In catalytic reactions, gold nanocluster catalysts are often protected by organic molecules like ANO1 (ANO0) basis set. These results were used to simulate anharmonic frequencies in the 2800- thiolates [2], because bare gold clusters are unstable and easily clump together into large particles. 3100 cm-1 region by VPT2+K simulations. Three bands in this region are purely harmonic in nature Gold-sulfur bonds formed on the surface of a gold nanocluster are thought to play a key role in stabilizing the cluster. On the other hand, it is known that thiolates do not efficiently stabilize Cu- while the remainder derive intensity from highly coupled anharmonic states corresponding to CH2 and Ag-clusters. Therefore, it is important to understand the nature of the coinage metal-sulfur bend overtones and combinations. As proposed by Schultz and co-workers,1 upon cyclobutyl ring bonds. For simple molecules like CuS [3], AgS [5], AuS [6], CuSH [7], AgSH [8], and AuSH [8], opening, the 1-methylallyl radical is formed as well as 1,3-butadiene, given a sufficient pyrolysis we and Ziurys group have already studied their rotational spectra and discussed their temperature. Evidence of allylcarbinyl radical, another intermediate proposed along this path, is not physico-chemical properties. observed. In this poster, we will report the first spectroscopic detection of the metal-bridged sulfur compounds H2S-MSH (M=Cu, Ag, and Au). These molecules were generated by the laser-ablation technique combined with the simultaneous electrical discharge, and their rotational spectra were observed by a Fourier transform microwave (FTMW) spectrometer. Although they are asymmetric rotors, only Ka=0 components were detected for H2S-CuSH and H2S-AuSH, both of which showed hyperfine splittings due to the Cu (I=3/2) and Au (I=3/2) nuclei, respectively. For H2S-AgSH without the hyperfine splittings, lines of the Ka=1 component as well as the Ka=0 component were observed. Measurement of deuterated isotopomers, HDS-MSH, H2S-MSD, HDS-MSD, D2S-MSH, and D2S-MSD were also carried out for each compound.

The observed transition frequencies of H2S-AgSH were analyzed by a Watson’s S-reduced Hamiltonian. For H2S-CuSH and H2S-AuSH, a simple Hamiltonian for a linear molecule was employed, because only transitions of the Ka=0 component was observed. The rotational constants obtained were interpreted into geometric information. It was suggested the derived structures were strongly affected by the zero-point vibrations, because of the coordinates of central metals are close to the center of the mass.

[1] M. Haruta, N. Yamada, T. Kobayashi, S. Iijima, J. Catal. 115, 301 (1989). [2] J. Akola, M. Walter, R. L. Whetten, H. Häkkinen, H. Grönbeck, J. Amer. Chem. Soc. 130, 3756 (2008). [3] J. M. Thompsen, L. M. Ziurys, Chem. Phys. Lett. 344, 75-84 (2001). [4] T. Okabayashi, A. Oya, T. Yamamoto, D. Mizuguchi, M. Tanimoto, J. Mol. Spectrosc. 329, 13 (2016). [5] S. Mizuno, M. Tokumoto, T. Okabayashi, Symposium on Molecular Spectroscopy (2012) [6] A. Janczyk, S. K. Walter, L. M. Ziurys, Chem. Phys. Lett. 401, 211 (2005). [7] T. Okabayashi, T. Yamamoto, D. Mizuguchi, E. Y. Okabayashi, M. Tanimoto, Chem. Phys. Lett. 551, 26 (2012). [8] T. Takahashi, H. Hashimoto, H. Kubota, E. Y. Okabayashi, T. Okabayashi, Annual Meeting of Japan Society for Molecular Science (2014)

References [1] J.C. Schultz, F.A. Houle, J.L. Beauchamp, J. Am. Chem. Soc. 106, 7336 (1984).

114 117115 B20

Detection of the simplest Criegee intermediate CH2OO in the ν4 band using a continuous wave quantum cascade laser and its kinetics with SO2 and NO2

a) a) Junting Qiu , Kenichi Tonokura

a)Department of Environment Systems, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8563, Japan

Mid-infrared absorption spectroscopy with a quantum cascade laser (QCL) has been applied to the detection of the simplest Criegee intermediate (CH2OO) in pulsed laser photolysis combined with a laser absorption kinetics reactor. Transitions of the ν4 vibrational band were probed with a thermoelectrically cooled, continuous wave mid-infrared distributed feedback QCL. The CH2OO was generated from the photolysis of CH2I2 /O2 mixtures at 266 nm. The mid-infrared absorption -1 spectrum of the CH2OO was recorded between 1273 and 1277 cm . Seperated absoption lines were observed in the spectrum of the CH2OO which was recorded with this high resolution method, and the results could help to modify the values of the rotational constants A, B, C for the CH2OO.

The rate coefficients for the reaction of CH2OO with SO2 and NO2 at 295 K were determined by probing the IR absorption at 1273.5 cm-1 to be (3.7 ± 0.2) × 10-11 cm3 molecule-1 s-1 and (1.9 ± 0.2) × 10-11 cm3 molecule-1 s-1, respectively, which were in good agreement with previous [1][2][3][4] measurements .Mid-infrared absorption detection of the CH2OO using a QCL as a spectroscopic light source is a powerful method in spectroscopic and kinetics studies of the CH2OO.

References [1] O.Welz, J. D. Savee, D. L. Osborn, S. S.Vasu, C. J. Percival, D. E. Shallcross, and C. A. Taatjes, Science, 335, 204-207 (2012). [2] L. Sheps, J. Phys. Chem. Lett., 4, 4201–4205 (2013). [3] Rabi Chhantyal-Pun, Anthony Davey, Dudley E. Shallcross, Carl J. Percival and Andrew J.Orr-Ewing, Phys.Chem.Chem.Phys., 17, 3617-362 (2015). [4] Daniel Stone, Mark Blitz, Laura Daubney, Neil U. M. Howes and Paul Seakins, Phys.Chem.Chem.Phys.,

16, 1139-1149 (2014).

118116 B21

Detection of the simplest Criegee intermediate CH2OO in the ν4 Different formation mechanisms of highly excited halogens band using a continuous wave quantum cascade laser and its following the multiphoton photolysis of halomethanes kinetics with SO2 and NO2 Bor-Chen Chang, Zheng-Jie Lin, and Cheng-Cian Wu a) a) Junting Qiu , Kenichi Tonokura Department of Chemistry, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan a)Department of Environment Systems, Graduate School of Frontier Sciences, The University of Tokyo, Emission spectra following the photolysis of bromomethanes (CBr4, CHBr3, CHBr2Cl, CHBrCl2, and CH2Br2) and iodomethanes (CHI3, CH2I2, CH3I, and CH2ICl) at different ultraviolet Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8563, Japan wavelengths were recorded in a slow flow cell at ambient temperature for investigating the formation mechanisms of highly excited atomic halogen.1,2 This work improved the experimental conditions to obtain better signal-to-noise ratios in the emission spectra, and several newly observed Mid-infrared absorption spectroscopy with a quantum cascade laser (QCL) has been applied to the transitions of atomic bromine were found. Power dependence and pressure dependence detection of the simplest Criegee intermediate (CH2OO) in pulsed laser photolysis combined with a measurements were also conducted. Although the emission spectrum of excited atomic bromine laser absorption kinetics reactor. Transitions of the ν4 vibrational band were probed with a following the photolysis is similar to that of excited atomic iodine, there exist prominent differences in their formation mechanisms. New results indicate that the formation mechanism of excited thermoelectrically cooled, continuous wave mid-infrared distributed feedback QCL. The CH OO 1 2 atomic bromine is a 4-photon process instead of a 3-photon process reported in the previous study, 2 was generated from the photolysis of CH2I2 /O2 mixtures at 266 nm. The mid-infrared absorption while it is a 3-photon process in the formation of excited atomic iodine. For these bromomethanes, -1 the photolysis wavelength dependences of the excited atomic bromine formation were acquired and spectrum of the CH2OO was recorded between 1273 and 1277 cm . Seperated absoption lines were exhibit a similar decreasing trend from 266 nm to 300 nm with a threshold at approximately 273 nm. observed in the spectrum of the CH2OO which was recorded with this high resolution method, and On the other hand, the corresponding studies of the excited atomic iodine generation following the the results could help to modify the values of the rotational constants A, B, C for the CH2OO. photolysis of iodomethanes show a threshold wavelength at roughly 276 nm and a resonant band at approximately 298 nm. Based on the available data, we speculate that the possible mechanism for The rate coefficients for the reaction of CH2OO with SO2 and NO2 at 295 K were determined by -1 -11 3 -1 -1 the formation of highly excited atomic bromine is a 1+3 multiphoton process, but it is a 2+1 probing the IR absorption at 1273.5 cm to be (3.7 ± 0.2) × 10 cm molecule s and (1.9 ± 0.2) multiphoton process for forming highly excited atomic iodine. × 10-11 cm3 molecule-1 s-1, respectively, which were in good agreement with previous measurements[1][2][3][4].Mid-infrared absorption detection of the CH OO using a QCL as a References 2 [1] S.-X. Yang, G.-Y. Hou, J.-H. Dai, C.-H. Chang, and B.-C. Chang, J. Phys. Chem. A 114, 4785 (2010). spectroscopic light source is a powerful method in spectroscopic and kinetics studies of the CH2OO. [2] C.-P. Tu, H.-I Cheng, and B.-C . Chang, J. Phys. Chem. A 117, 13572 (2013).

References [1] O.Welz, J. D. Savee, D. L. Osborn, S. S.Vasu, C. J. Percival, D. E. Shallcross, and C. A. Taatjes, Science, 335, 204-207 (2012). [2] L. Sheps, J. Phys. Chem. Lett., 4, 4201–4205 (2013). [3] Rabi Chhantyal-Pun, Anthony Davey, Dudley E. Shallcross, Carl J. Percival and Andrew J.Orr-Ewing, Phys.Chem.Chem.Phys., 17, 3617-362 (2015). [4] Daniel Stone, Mark Blitz, Laura Daubney, Neil U. M. Howes and Paul Seakins, Phys.Chem.Chem.Phys.,

16, 1139-1149 (2014).

116 119117 B22

Ultrafast Photoemission Spectroscopy of Liquid Water using Ultrashort 134 nm Pulses

Yo-ichi Yamamotoa) and Toshinori Suzukia)

a)Department of Chemistry, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan

Hydrated electron is one of the most fundamental quantum systems in liquid, and it attracts great attention from the viewpoints of radiation chemistry, biology and quantum physics [1, 2]. For generating hydrated electron in the laboratory, two-photon excitation and dissociation of liquid water at 267 nm has often been employed. However, strong UV excitation pulses may have induced unwanted multiphoton effects [3]. Therefore, in this study, we employed 134-nm pulses to perform ultrafast photoemission spectroscopy of liquid water using one-photon excitation. An output of Ti:Sa laser was split into two. One beam was frequency-doubled in a BBO crystal and loosely focused into a gas cell filled with Ar (~10 Torr) to generate 134 nm pulses [4]. The other output beam was frequency-tripled using two BBO crystals. The cross correlation between the 134 and 267 nm pulses was ca. 100 fs. These pulses were focused onto a 25-m diameter liquid microjet of a 50 mM NaCl aqueous solution and the electron kinetic energy distributions (eKEDs) of emitted photoelectrons were measured using a magnetic bottle time-of-flight electron energy analyzer. The eKED exhibited rapid shift toward low energy with the pump-probe delay time. The shift ceased within 3 ps and the peak eKE stayed at 0.85 eV, which is a signature of the ground state hydrated electron [5]. The global fit of the obtained data provided two time constants of 300 and 840 fs, which are ascribed respectively to solvation of hot electrons and to recombination with OH radical. In addition, we have performed 267 nm two-photon excitation experiment to compare the results. The results obtained by 134-nm one-photon and 267-nm two-photon excitation were essentially identical except for a strong impulsive signal observed with two-photon excitation. For further examination of the - electron dynamics, we have added NO3 as a scavenger of hydrated electron to find that only - the shorter time constant changed with the NO3 concentration. Since electron scavenging cross-section scales with the size of electron cloud [6], the result suggests that the first component has a diffuse electron cloud. On the other hand, even though the lifetime of the fast component diminishes, the rate of eKED shift was invariant with scavenging, which indicates that eKED shift is due to a wave packet motion on an adiabatic potential. Figure. The eKEDs as a function of delay time for (a) 134 nm one-photon and (b) 267 nm two-photon.

References [1]E. Alizadeh et al., Chem. Rev. 112, 5578 (2012) [2]L. Turi et al., Chem. Rev. 112, 5641 (2012) [3]C.-R. Wang et al., Phys. Chem. Chem. Phys. 10, 4463 (2008) [4]P. Trabs et al. in Conference on Lasers and Electro-Optics, OSA Technical Digest (online), paper FM4A.4. (2016) [5]Y. Yamamoto et al., J. Phys. Chem. A 120, 1153 (2016) [6]T. W. Kee et al., J. Phys. Chem. A 105, 8434 (2001)

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Ultrafast Photoemission Spectroscopy of Liquid Water HO2 yield in the reaction of different peroxy radicals with OH using Ultrashort 134 nm Pulses radicals

Yo-ichi Yamamotoa) and Toshinori Suzukia) Christa Fittschena), Emmanuel Assafa), and Coralie Schoemackera) a)Department of Chemistry, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan a)CNRS - University Lille,Bât. C11, Cité Scientifique,Villeneuve d’Ascq, France

Hydrated electron is one of the most fundamental quantum systems in liquid, and it Peroxy radicals, RO2, are key species in the atmosphere. They are formed from a reaction of OH attracts great attention from the viewpoints of radiation chemistry, biology and quantum physics [1, radicals with hydrocarbon: 2]. For generating hydrated electron in the laboratory, two-photon excitation and dissociation of RH + OH + O → RO + H O liquid water at 267 nm has often been employed. However, strong UV excitation pulses may have 2 2 2 induced unwanted multiphoton effects [3]. Therefore, in this study, we employed 134-nm pulses to In polluted environments, RO2 radicals react predominantly with NO, leading to formation of NO2 perform ultrafast photoemission spectroscopy of liquid water using one-photon excitation. and eventually through photolysis of NO2 to formation of O3. An output of Ti:Sa laser was split into two. One beam was frequency-doubled in a BBO At low NOx concentrations such as in the marine boundary layer or the background troposphere, the crystal and loosely focused into a gas cell filled with Ar (~10 Torr) to generate 134 nm pulses [4]. lifetime of RO2 radicals increases and other reaction pathways become competitive. Atmospheric The other output beam was frequency-tripled using two BBO crystals. The cross correlation chemistry models have considered until recently only the self- and cross reaction with other RO2 between the 134 and 267 nm pulses was ca. 100 fs. These pulses were focused onto a 25-m radicals or with HO2 radicals as the major fate for RO2 radicals under low NOx conditions. Recently, diameter liquid microjet of a 50 mM NaCl aqueous solution and the electron kinetic energy the rate constants for the reaction of peroxy radicals with OH radicals distributions (eKEDs) of emitted photoelectrons were measured using a magnetic bottle RO + OH → products time-of-flight electron energy analyzer. 2 The eKED exhibited rapid shift toward low energy with the pump-probe delay time. The has been measured for CH3O2 [1, 2] and C2H5O2 [3] and it was shown to become competitive to shift ceased within 3 ps and the peak eKE stayed at 0.85 eV, which is a signature of the ground state other sinks [4]. However, in order to evaluate the impact of this so far neglected sink for peroxy hydrated electron [5]. The global fit of the obtained data provided two time constants of 300 and radicals on the composition of remote atmospheres, the reaction products must be known. 840 fs, which are ascribed respectively to solvation of hot electrons and to recombination with OH A recently improved experimental set-up combining laser photolysis with two simultaneous radical. In addition, we have performed 267 nm cw-CRDS detections in the near IR allowing for a time resolved, absolute quantification of OH and two-photon excitation experiment to compare RO2 radicals has been used for a further investigation of this class of reactions. High-repetition rate the results. The results obtained by 134-nm LIF is used for determining relative OH profiles. one-photon and 267-nm two-photon excitation were essentially identical except for a strong impulsive signal observed with two-photon excitation. For further examination of the - electron dynamics, we have added NO3 as a scavenger of hydrated electron to find that only - the shorter time constant changed with the NO3 concentration. Since electron scavenging cross-section scales with the size of electron cloud [6], the result suggests that the first component has a diffuse electron cloud. On the other hand, even though the lifetime of the fast component diminishes, the rate of eKED shift was invariant with scavenging, which indicates For CH O radicals, HO has been determined as major product recently [5]. Currently, we study the that eKED shift is due to a wave packet motion 3 2 2 next larger perxoy, C H O , using different radical precursors (C H5 , (COCl) /C H , XeF /C H ) on an adiabatic potential. Figure. The eKEDs as a function of delay time for 2 5 2 2 I 2 2 6 2 2 6 and also deuterated C D I in order to elucidate the product yield. Preliminary results show a much (a) 134 nm one-photon and (b) 267 nm two-photon. 2 5 lower HO2 yield for C2H5O2 compared to CH3O2. The most recent results will be presented at the conference.

[1] A. Bossolasco, E. Faragó, C. Schoemaecker, and C. Fittschen, CPL, 593, 7, (2014). References [1]E. Alizadeh et al., Chem. Rev. 112, 5578 (2012) [2]L. Turi et al., Chem. Rev. 112, 5641 (2012) [3]C.-R. [2] E. Assaf, B. Song, A. Tomas, C. Schoemaecker, C. Fittschen, JPC A, 120, 8923 (2016) Wang et al., Phys. Chem. Chem. Phys. 10, 4463 (2008) [4]P. Trabs et al. in Conference on Lasers and [3] Eszter Faragó, Coralie Schoemaecker, Bela Viskolcz, and Christa Fittschen, CPL, 619, 196, (2015). Electro-Optics, OSA Technical Digest (online), paper FM4A.4. (2016) [5]Y. Yamamoto et al., J. Phys. Chem. A [4] Christa Fittschen, Lisa Whalley, and Dwayne Heard, EST, 118, 7700, (2014). 120, 1153 (2016) [6]T. W. Kee et al., J. Phys. Chem. A 105, 8434 (2001) [5] E. Assaf, L. Sheps, L. Whalley, D. Heard, A. Tomas, C. Schoemaecker, C. Fittschen, EST, 51, 2170 (2017)

118 121119 B24

Development of a novel method for determination of a ratio between HO2 and RO2 generation paths in HOx cycle

Nanase KOHNOa), Kensuke Itoa), Yosuke SAKAMOTOa, b) and Yoshizumi KAJIIa, b)

a) Kyoto University, Nihonmatsucho, Sakyo-ku, Kyoto, Japan b) National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba-shi, Ibaragi, Japan

HOx cycle plays an important role in the troposphere (Fig. 1). For detailed understanding of the atmospheric composition, quantitative evaluation of each steps in HOx cycle is necessary. If all species related to HOx cycle can be identified, it is possible to estimate the branching ratio of each steps. However, it is not practical since there are more than 100 kinds of trace species. In this study, we have employed the laser pump and probe techniques to detect HO2 and RO2 radicals and to evaluate the branching ratio between the total RO2 and HO2 formation paths in the presence of gaseous mixture of CO and VOCs (Fig. 1, (a) and (b)). First, OH was generated by the irradiation with a pump light Fig. 1. A schematic diagram of (266 nm) to the gaseous mixture (Ptot = 760 Torr) of zero air/O3 in a fundamental reactions related to flow cell (reaction cell). Then, a part of gaseous was introduced HOx cycle. into a second cell (detection cell) through an aperture. The total pressure of the detection cell was kept at about 2 Torr. OH was detected by the laser-induced fluorescence (LIF) technique via AX transition. Recorded time-resolved LIF of OH are shown in Fig. 2A. When CO and VOCs were added into the reaction cell, OH decayed fast due to the following reactions, respectively (as shown in the Fig. 2B (a), 2C (a)): OH + CO  H + CO2 (1a) H + O2 + M  HO2 + M (1b) OH + RH  R + H2O (2a) R + O2 + M  RO2 + M (2b). And then, when NO was added into the detection cell, the LIF intensity of OH increased due to the reaction, HO2 + NO  OH + NO2 (Fig. 2B (b)). Furthermore, RO2 were also converted into OH by the following reactions (Fig. 2C (b)): O2 + NO  RO + NO2 (3a) RO + O2  HO2 + carbonyl compounds (3b) HO2 + NO  OH + NO2 (3b). Fig. 2. Time-resolved LIF Thus, the subtraction of profiles a from b (Fig. 2B, 2C) are intensities of OH. (B) P(CO) = 0.1 those of HO2 and RO2, respectively. In this study, we Torr at the reaction cell. (C) applied C3H6 to detect RO2. NO concentration dependences of time profiles were also P(C3H6) = 0.6 mTorr at the reaction measured. The intensity of RO2 disappeared at much lower cell. Profiles b were recorded in the NO concentration, because the conversion of RO2 to OH presence of NO (P(NO) = 3 mTorr) required twice NO as high as that of HO2. In other words, at the detection cell. HO2 can be detected selectively at lower NO concentration, and HO2 and RO2 are detected simultaneously at sufficiently high NO concentration. From the different dependences for NO concentrations between the HO2 and RO2 formation paths, we tried to determine the branching ratio between these two paths in presence of the gaseous mixture (CO/C3H6).

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Development of a novel method for determination of a ratio Direct measurement of HOX (OH and HO2) radical uptake onto between HO2 and RO2 generation paths in HOx cycle aerosols by a laser photolysis generation and probe techniques

Nanase KOHNOa), Kensuke Itoa), Yosuke SAKAMOTOa, b) and Yoshizumi KAJIIa, b) Yosuke Sakamotoa,b,c), Maho Nakagawaa), Nanase Kohnoa), Jun Hirokawad), Yoshizumi Kajii a,b,c) a) Kyoto University, Nihonmatsucho, Sakyo-ku, Kyoto, Japan b) National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba-shi, Ibaragi, Japan a) Graduate School of Global Environmental Studies, Kyoto University, Kyoto, Japan b) Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan c) HOx cycle plays an important role in the troposphere (Fig. 1). Center for Regional Environmental Research, National Institute for Environmental Studies, Ibaraki, Japan d) For detailed understanding of the atmospheric composition, Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan. quantitative evaluation of each steps in HOx cycle is necessary. If all species related to HOx cycle can be identified, it is possible to It has been recognized that aerosols in the atmosphere have an impact on both climate and human estimate the branching ratio of each steps. However, it is not health. Aerosols change their physical and chemical properties through HOX (OH + HO2) radical [1] practical since there are more than 100 kinds of trace species. In uptake, which is expected to be one of the most important atmospheric aging processes. Since the this study, we have employed the laser pump and probe techniques aerosols’ effect depends on their properties, rate constants for HOX radical uptake, namely uptake to detect HO2 and RO2 radicals and to evaluate the branching ratio coefficients, are required to quantify the accurate impact of aerosols on climate and health. However, between the total RO2 and HO2 formation paths in the presence of due to methodological limitations, uptake efficiency by multicomponent aerosols in reaction gaseous mixture of CO and VOCs (Fig. 1, (a) and (b)). systems, e.g. chamber experiments and atmosphere, is still uncertain. First, OH was generated by the irradiation with a pump light We are developing a novel technique for direct HOX radical uptake measurement with a Fig. 1. A schematic diagram of combination of laser photolysis generation and laser-induced fluorescence detection, in order to (266 nm) to the gaseous mixture (Ptot = 760 Torr) of zero air/O3 in a fundamental reactions related to flow cell (reaction cell). Then, a part of gaseous was introduced investigate the uptake by multicomponent aerosols with a high time resolution. In the case of OH HOx cycle. into a second cell (detection cell) through an aperture. The radical uptake measurement, sample air containing aerosols, water vapor and ozone is introduced to total pressure of the detection cell was kept at about 2 Torr. a reaction cell, followed by pulsed laser irradiation (266 nm) at a repetition rate of 1 Hz to produce OH was detected by the laser-induced fluorescence (LIF) OH radical through photolysis of O3 and sequential reaction: O3 + H2O + hv  2OH + O2. A part of technique via AX transition. Recorded time-resolved LIF sample air is continuously introduced into a detection cell and time variation of OH radical is of OH are shown in Fig. 2A. monitored by laser-induced fluorescence detection at a repetition rate of 10 kHz. Observed OH When CO and VOCs were added into the reaction cell, radical decay can be expressed with first order rate constants of aerosol uptake by aerosols, OH decayed fast due to the following reactions, respectively reactions with gas phase species and background diffusion loss. (as shown in the Fig. 2B (a), 2C (a)):  d[OH] OH + CO H + CO2 (1a)  k '(total)[OH]k '(uptake) kk '(gas) '(loss) [OH] (E1) H + O2 + M  HO2 + M (1b) dt OH + RH  R + H2O (2a)  kS'(uptake)   OH (E2) R + O2 + M  RO2 + M (2b). 4 And then, when NO was added into the detection cell, the LIF intensity of OH increased due to the reaction, HO2 + where  OH and S denote uptake coefficient, thermal mean velocity of OH radical and surface area NO  OH + NO2 (Fig. 2B (b)). Furthermore, RO2 were also concentration of aerosols, respectively. Analyzing OH radical decay, the uptake coefficient can be converted into OH by the following reactions (Fig. 2C (b)): obtained. O2 + NO  RO + NO2 (3a) In a way similar to OH radical uptake measurement, the HO2 radical uptake can be measured, with RO + O2  HO2 + carbonyl compounds (3b) CO addition in the reaction cell to convert OH radical into HO2 radical and with NO addition in the HO2 + NO  OH + NO2 (3b). detection cell to re-convert HO2 radical into OH radical. Fig. 2. Time-resolved LIF Thus, the subtraction of profiles a from b (Fig. 2B, 2C) are This method can provide aerosol reactivity with a time resolution of few minutes and would be intensities of OH. (B) P(CO) = 0.1 those of HO2 and RO2, respectively. In this study, we applied to an in-situ uptake measurement in the reaction system. We will show recent results in HOX Torr at the reaction cell. (C) applied C3H6 to detect RO2. radical uptake measurement with the present method. NO concentration dependences of time profiles were also P(C3H6) = 0.6 mTorr at the reaction measured. The intensity of RO2 disappeared at much lower cell. Profiles b were recorded in the References NO concentration, because the conversion of RO2 to OH presence of NO (P(NO) = 3 mTorr) [1] I. J. George and J. P. D. Abbatt, Nature Chemistry, 2, 713-722 (2010). required twice NO as high as that of HO2. In other words, at the detection cell. [2]A. K. Bertram et al., J. Phys. Chem. A, 105, 9415-9421 (2001). [3] J. D. Smith et al., Atmos. Chem. Phys., 9, 3209-3222 (2009). HO2 can be detected selectively at lower NO concentration, and HO2 and RO2 are detected simultaneously at sufficiently high NO concentration. From the different dependences for NO [4] F. Taketani et al., Atmos. Chem. Phys., 12, 1907-11916 (2012). concentrations between the HO2 and RO2 formation paths, we tried to determine the branching ratio between these two paths in presence of the gaseous mixture (CO/C3H6).

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Laser photodissociation spectroscopy of protonated N-aromatic ions:

Adam J. Trevitt1, S. J. Blanksby2, C. S. Hansen1, J. P. Bezzina1, B. McKinnon1

1University of Wollongong, Australia 2Queensland University of Technology, Australia agents and fluorescent tags. Despite their wide-spread use, there is a lack of information about their photostability and fate – particularly for their protonated variants. These details are vital to support models of photochemistry involving proton-transfer, electron-transfer and internal conversation. Generally, modelling excited-state processes is not routine and therefore experimental data are required to guide the construction of sound models and computational tools.

We use a combination of ion-trap mass spectrometry and tunable UV-Vis pulsed laser radiation to detect and measure the wavelength-dependent generation of photoproducts. Computational results for excited-states and ground state photodissociation pathways assist in assigning the spectra.

In recent results, we have examined the action spectroscopy of ethynylpyridineH+ and formylpyridineH+ ions (ortho, meta and para in each case) for the first time to examine how these substituents on pyridinium ion affect the photodissociation pathways and spectroscopy. UV photodissociation spectra are measured - which in some case exhibit vibronic detail - and multiple photodissociation channels are detected.

For the case of ethynylpyridinium ions, photodissociation pathways lead to either retention of the N atom in the ring (from C2H2 elimination) or its expulsion (with HCN elimination) - and presently it’s not clear what mediates the photodissociation. Are there common intermediate states? Our group is trying to rationalise some guiding principles to understand and predict photodissociation of protonated N-containing aromatics.

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Laser photodissociation spectroscopy of Theoretical Study on the Substituent Effect in Criegee protonated N-aromatic ions: Intermediate Reactions

Adam J. Trevitt1, S. J. Blanksby2, C. S. Hansen1, J. P. Bezzina1, B. McKinnon1 Kaito Takahashia), and Cangtao Yina)

1University of Wollongong, Australia a) Institute of Atomic and Molecular Sciences, Academia Sinica No. 1, Roosevelt Rd., Sec. 4, Taipei, 10617, 2Queensland University of Technology, Australia Taiwan agents and fluorescent tags. Despite their wide-spread use, there is a lack of information about their Due to its fast reaction rate with SO2, carbonyl oxides or Criegee intermediates (CIs) are photostability and fate – particularly for their protonated variants. These details are vital to support thought to be important oxidizing agents in the atmosphere. However, in highly humid atmospheric models of photochemistry involving proton-transfer, electron-transfer and internal conversation. conditions, CIs with hydrogen in the syn-conformation of the OO bond, such as CH2OO, react Generally, modelling excited-state processes is not routine and therefore experimental data are quickly with water vapor to form hydroperoxy alcohols. Since these alcohols do not react with SO2, required to guide the construction of sound models and computational tools. this reaction of CI with water decreases the ability for CIs to act as oxidizing agents in the atmosphere. Furthermore, it has been found that for CIs with an alkyl group in the syn-conformation We use a combination of ion-trap mass spectrometry and tunable UV-Vis pulsed laser radiation to of the OO bond, such as (CH3)2COO, the hydrogen abstraction unimolecular reaction forming vinyl detect and measure the wavelength-dependent generation of photoproducts. Computational results peroxide can occur at very fast rates. Once again these vinyl peroxides also show low reactivity for excited-states and ground state photodissociation pathways assist in assigning the spectra. toward SO2. Compared to the detailed studies performed for CH2OO, CH3CHOO, and (CH3)2COO, studies In recent results, we have examined the action spectroscopy of ethynylpyridineH+ and toward CH3CH2CHOO is much scarce. In this study, we examine the substituent dependence in formylpyridineH+ ions (ortho, meta and para in each case) for the first time to examine how these the CI’s reactivity toward water vapor and unimolecular reaction. Starting from the simplest CI: substituents on pyridinium ion affect the photodissociation pathways and spectroscopy. UV CH2OO, we calculated for CH3CHOO, CH3CH2CHOO, and (CH3)2COO. Furthermore, to clarify the photodissociation spectra are measured - which in some case exhibit vibronic detail - and multiple effect of unsaturated carbon bonds, we have also calculated CH2CHCHOO as well as CHCCHOO. photodissociation channels are detected. Since the CIs that are obtained from the ozonolysis of biogenetic alkenes include unsaturated carbon bonds, we think the systematic study on these C3 CI will provide a good estimate for the CIs in the For the case of ethynylpyridinium ions, photodissociation pathways lead to either retention of the N atmosphere. We performed ab initio calculations and obtained the bimolecular rate coefficients atom in the ring (from C2H2 elimination) or its expulsion (with HCN elimination) - and presently it’s between CIs and H2O as well as (H2O)2. Furthermore, we performed small curvature tunneling not clear what mediates the photodissociation. Are there common intermediate states? Our group is calculations to obtain accurate rate coefficients for the hydrogen transfer unimolecular reactions for trying to rationalise some guiding principles to understand and predict photodissociation of these longer chain CIs. protonated N-containing aromatics.

References [1] C. Yin, and K. Takahashi Physical Chemistry Chemical Physics, 19, 12075 – 12084 (2017). [2] L.-C. Lin, W. Chao, M. Smith, J. Lin, and K. Takahashi Physical Chemistry Chemical Physics, 18, 4557-4568 (2016).

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Diffuse Interstellar Bands; 100-years-old Mystery beginning to be solved? Takeshi Oka

Department of Astronomy and Astrophysics, and Department of Chemistry, The Enrico Fermi Institute, University of Chicago

The Diffuse Interstellar Bands (DIBs) are a group of many broad absorption bands mainly in the visible first observed by A. J. Cannon more than 100 years ago. D. G. York at the University of Chicago leads a team of 10 DIBs astronomers to which I belong. We have observed ~ 500 DIBs toward ~ 300 stars in all directions of the sky. They demonstrate the ubiquitous presence of an enormous amount of large organic molecules in interstellar space. A sizable fraction of carbon atoms in the Universe are locked up in the carriers of DIBs. Many astronomers, spectroscopists, and chemists speculated on the identity of the carriers of DIBs only to fail. Two years ago, however, after many years of systematic laboratory investigations, J. P. + Maier demonstrated that two (later 5) lines of C60 match with DIBs [1]. This was initially speculated by Foing and Ehrenfreund in 1994 [2] based on Maier’s 1993 matrix spectrum [3] but it took Maier + 22 years to obtain the spectrum of gaseous C60 at the low temperature of interstellar space. + If C60 explains 5 spectral lines, there need to be ~ 100 organic molecules to cause the observed 500 DIB lines. Currently popular candidates for the carriers of DIBs are fulleranes, PAHs, and carbon chains. I favor carbon chains although many have been already tested by Maier. There is no use to aimlessly ramble through observed data. We need some special star or DIB as a “Rosetta Stone” to test the idea. In 2013, we discovered spectacular DIBs with Extended Tails toward Reds (ETRs) toward the special star Herschel 36 [4]. Out of the 300 stars we observed this is the only one which clearly shows the ETRs. Also DIBs toward the star are sharply divided into two groups one clearly showing ETRs and the other where the ETRs are totally absent. I used this as the Rosetta Stone to develop a model calculation of thermalization by collisions and radiations and concluded that ETRs are due to radiative pumping of rotational levels of the carrier molecules and the DIBs with and without ETRs are due to polar and non-polar molecules, respectively. Spectroscopically, the ETRs are a result of decrease of rotational constant upon electronic excitation like R-branch head. A detailed analysis suggested that the carrier molecules are carbon chain molecules with ~ 6 carbon atoms [5]. As for the Rosetta stone of DIBs I chose λ5797 DIB whose very characteristic line shape was noted by the ultrahigh resolution observations toward ζ Oph by P. J. Sarre’s group [6]. Together with an undergraduate student Jane Huang, I showed that this DIB is best explained as due to a parallel band of prolate top with ~ 6 carbon atoms [7]. Currently I am working with another undergraduate student to investigate spectra of Red Rectangle where this DIB is observed in emission. In view of the low temperature and low density of the diffuse interstellar medium, it seems highly unlikely that those large carbon molecules are produced bottom up from atoms and simple molecules as in dense clouds. They must be produced top down from decomposition of dust by cosmic rays, + shocks, and VUV photons [8]. The discovery of C60 seems to put a nail on the coffin on this idea.

References [1] E. K. Campbell, M. Holz, D. Gerlich & J. P. Maier,. Nature, 523, 322 (2015) [2] B. H. Foing & P. Ehrenfreund, Nature, 369, 296 (1994) [3] J. Fulara, M. Jakobi, & J. P. Maier, Chem. Phys. Lett., 211, 227 (1993) [4] J. Dahlstrom, D. G. York, D. E. Welty, T. Oka, L. M. Hobbs, S. Johnson, S. D. Friedman, Z. Jiang, B. L. Rachford, R. Sherman, T. P. Snow, & P. Sonnentrucker, ApJ, 773, 41 (2013) [5] T. Oka, D. E. Welty, S. Johnson, D. G. York, J. Dahlstrom, & L. M. Hobbs, ApJ, 773:42 (2013) [6] T. H. Kerr, R. E. Hibbins, S. J. Fossey, J. R. Miles, & P. J. Sarre, ApJ, 495, 941 (1998) [7] J. Huang & T. Oka, Mol. Phys. 113, 2159 (2015) [8] T. Oka & A. N. Witt, RH15, 71st International Symposium on Molecular Spectroscopy (2016)

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Diffuse Interstellar Bands; 100-years-old Mystery beginning to Sub-Doppler molecular spectroscopy with a frequency comb be solved? referenced optical parametric oscillator Takeshi Oka Lauri Halonen, Juho Karhu, Markku Vainio, and Markus Metsälä Department of Astronomy and Astrophysics, and Department of Chemistry, The Enrico Fermi Institute, Department of Chemistry, University of Helsinki, Helsinki, Finland University of Chicago

The Diffuse Interstellar Bands (DIBs) are a group of many broad absorption bands mainly in the Optical frequency combs (OFC) can be used as accurate optical frequency references, which makes them valuable tools in spectroscopy and kinetics, when applied to various molecular species visible first observed by A. J. Cannon more than 100 years ago. D. G. York at the University of including free radicals. A laser source locked to an OFC reference has a stable and accurately known Chicago leads a team of 10 DIBs astronomers to which I belong. We have observed ~ 500 DIBs wavelength, which is advantageous in applications that require high resolution, such as sub-Doppler toward ~ 300 stars in all directions of the sky. They demonstrate the ubiquitous presence of an spectroscopy. For spectroscopy, an important prospect is the expansion of the OFC technologies into enormous amount of large organic molecules in interstellar space. A sizable fraction of carbon atoms the mid-infrared wavelength region, where the strong fundamental vibrational transitions are found in the Universe are locked up in the carriers of DIBs. [1]. We have produced a fully-stabilized mid-infrared OFC using a synchronously pumped Many astronomers, spectroscopists, and chemists speculated on the identity of the carriers of DIBs degenerate femtosecond optical parametric oscillator (fs-OPO) [2]. This comb serves as a direct only to fail. Two years ago, however, after many years of systematic laboratory investigations, J. P. frequency reference for the stabilization of the idler wavelength of a continuous-wave optical + Maier demonstrated that two (later 5) lines of C60 match with DIBs [1]. This was initially speculated parametric oscillator (CW-OPO), which was used as a light source in molecular laser spectroscopy. by Foing and Ehrenfreund in 1994 [2] based on Maier’s 1993 matrix spectrum [3] but it took Maier We have utilized the OFC stabilized CW-OPO in two sub-Doppler spectroscopy experiments with + 22 years to obtain the spectrum of gaseous C60 at the low temperature of interstellar space. the resolution and accuracy below 1 MHz. First, we performed saturation spectroscopy of methane + If C60 explains 5 spectral lines, there need to be ~ 100 organic molecules to cause the observed in a Lamb-dip configuration. The frequency stabilized CW-OPO idler beam was reflected back and 500 DIB lines. Currently popular candidates for the carriers of DIBs are fulleranes, PAHs, and carbon forth through a 50 cm cuvette containing 30 mTorr of methane. The idler wavelength was chains. I favor carbon chains although many have been already tested by Maier. There is no use to modulated through the pump beam. The first derivative signal of the Lamb-dip was recorded with a aimlessly ramble through observed data. We need some special star or DIB as a “Rosetta Stone” to lock-in amplifier (Fig. 1). The idler wavelength was scanned by tuning the OFC reference. test the idea. The stabilized CW-OPO was also used in a two-photon vibrational spectroscopy setup [3]. The In 2013, we discovered spectacular DIBs with Extended Tails toward Reds (ETRs) toward the CW-OPO pumps a strong mid-infrared transition of acetylene, and a second transition, from the special star Herschel 36 [4]. Out of the 300 stars we observed this is the only one which clearly shows pumped state to an infrared-inactive vibrational state, is recorded with an external-cavity diode laser the ETRs. Also DIBs toward the star are sharply divided into two groups one clearly showing ETRs (ECDL). The ECDL is itself stabilized to the near-infrared OFC that also pumps the fs-OPO. With a and the other where the ETRs are totally absent. I used this as the Rosetta Stone to develop a model free-running CW-OPO, the time available for the measurement of the spectrum is limited to a few calculation of thermalization by collisions and radiations and concluded that ETRs are due to radiative seconds, since the CW-OPO long-term frequency drifts are larger than the linewidth of the pumping of rotational levels of the carrier molecules and the DIBs with and without ETRs are due to two-photon transition. With the stabilized CW-OPO and ECDL, we could resolve the shape of the polar and non-polar molecules, respectively. Spectroscopically, the ETRs are a result of decrease of narrow, sub-Doppler transition line with high resolution and a high signal-to-noise ratio (Fig. 1). rotational constant upon electronic excitation like R-branch head. A detailed analysis suggested that the carrier molecules are carbon chain molecules with ~ 6 carbon atoms [5]. As for the Rosetta stone of DIBs I chose λ5797 DIB whose very characteristic line shape was noted by the ultrahigh resolution observations toward ζ Oph by P. J. Sarre’s group [6]. Together with an undergraduate student Jane Huang, I showed that this DIB is best explained as due to a parallel band of prolate top with ~ 6 carbon atoms [7]. Currently I am working with another undergraduate student to investigate spectra of Red Rectangle where this DIB is observed in emission. In view of the low temperature and low density of the diffuse interstellar medium, it seems highly unlikely that those large carbon molecules are produced bottom up from atoms and simple molecules as in dense clouds. They must be produced top down from decomposition of dust by cosmic rays, + shocks, and VUV photons [8]. The discovery of C60 seems to put a nail on the coffin on this idea.

References Fig. On left: Lamb-dip spectrum of the methane symmetric CH-stretching vibration. Black dots [1] E. K. Campbell, M. Holz, D. Gerlich & J. P. Maier,. Nature, 523, 322 (2015) [2] B. H. Foing & P. Ehrenfreund, Nature, 369, 296 (1994) are the measured points and the solid line is their low-pass filtered average. The zero of the [3] J. Fulara, M. Jakobi, & J. P. Maier, Chem. Phys. Lett., 211, 227 (1993) frequency axis corresponds to the line center frequency 92 232 636.917 MHz. On right: [4] J. Dahlstrom, D. G. York, D. E. Welty, T. Oka, L. M. Hobbs, S. Johnson, S. D. Friedman, Z. Jiang, B. L. Rachford, Two-photon absorption spectrum of acetylene transition R(17) of the band ν1 + 2ν3 ← ν3. The R. Sherman, T. P. Snow, & P. Sonnentrucker, ApJ, 773, 41 (2013) spectrum is measured with cavity ring-down spectroscopy when the stabilized CW-OPO idler [5] T. Oka, D. E. Welty, S. Johnson, D. G. York, J. Dahlstrom, & L. M. Hobbs, ApJ, 773:42 (2013) beam pumps the J=17 rovibrational state of ν3. [6] T. H. Kerr, R. E. Hibbins, S. J. Fossey, J. R. Miles, & P. J. Sarre, ApJ, 495, 941 (1998) [1] M. Vainio and L. Halonen, Physical Chemistry Chemical Physics 18, 4266 (2016). [7] J. Huang & T. Oka, Mol. Phys. 113, 2159 (2015) [2] M. Vainio and J. Karhu, Optics Express 25, 4190 (2017). [8] T. Oka & A. N. Witt, RH15, 71st International Symposium on Molecular Spectroscopy (2016) [3] J. Karhu, M. Vainio, M. Metsälä, and L. Halonen, Optics Express 25, 4688 (2017).

124 127125 B30

Rotationally-Resolved High-Resolution Laser Spectroscopy of S1-S0 transition of Fluorene

Shunji Kasahara and Shinji Kuroda

Molecular Photoscience Research Center, Kobe University, Kobe 657-8501, Japan

High-resolution laser spectroscopy is a powerful tool for studying the structure and dynamics of excited polyatomic molecules in detail and unambiguously. High-resolution and high-accuracy of the spectral lines enable to observe rotationally-resolved electronic transition and to find out the excited state dynamics through the fairly deviation of the spectral line position, intensity anomaly and the change of the spectral linewidth. In this study, we have observed the rotationally- resolved high-resolution fluorescence excitation spectra of the Figure 1. Fluorene 1 1 S1 B2←S0 A1 transition for fluorene. The magnetic effect was also measured up to 1.2 T to consider the excited state dynamics. A molecular beam was obtained by expanding of Fluorene vapor with Ar gas through a pulsed nozzle into the vacuum chamber and collimated by using a skimmer and slit. Sub-Doppler fluorescence excitation spectra were measured by crossing a single-mode UV laser beam perpendicular to a collimated molecular beam. Absolute wavenumber was calibrated with accuracy 0.0002 cm-1 by measuring the Doppler-free saturation spectrum of iodine and a fringe pattern of the stabilized etalon. Rotationally-resolved high-resolution fluorescence excitation spectra of 0-0 band and six vibronic bands have been observed in the region of 33770-35000 cm-1 region. The typical linewidth is about 25 MHz which include the natural linewidth 10 MHz obtained from the reported lifetime15.6 ns. [1] The observed band were assigned as the a-type transition (selection rule: ∆K=0, ∆J=0, ±1) from the spectral pattern. For the 0-0 band, 2489 lines were assigned, and their molecular constants were determined with high accuracy. The obtained molecular constants are good agreement with the reported ones. [2] The observed rotational lines of the other vibronic bands were also assigned and determined their molecular constants, but some bands show the difficulty of the 0 -1 rotational assignment. Especially, the typical energy shift was found for the 00 + 204 cm band due to the local perturbation with another vibronic level in S1 state.

[1] A. R. Auty, A. C. Jones and D. Phillips, J. Chem. Soc., Faraday Trans. 2, 82, 1219 (1986) . [2] J. T. Yi, L. Alvarez-Valtierra and D. W. Pratt, J. Chem. Phys. 124, 244302 (2006) .

128126 B31

Rotationally-Resolved High-Resolution Laser Spectroscopy of Isomer-specific detection in the UV photodissociation of the S1-S0 transition of Fluorene propargyl radical by Chirped-Pulse mm-Wave spectroscopy Shunji Kasahara and Shinji Kuroda in a Pulsed Quasi-Uniform Flow

Molecular Photoscience Research Center, Kobe University, Kobe 657-8501, Japan Bernadette M. Broderick, Nureshan Dias, Nicolas Suas-David and Arthur G. Suits

High-resolution laser spectroscopy is a powerful tool for Department of Chemistry, University of Missouri Columbia MO 65211 studying the structure and dynamics of excited polyatomic molecules in detail and unambiguously. High-resolution and The UV photodissociation of the propargyl radical has been investigated by high-accuracy of the spectral lines enable to observe rotationally-resolved electronic transition and to find out the Chirped-Pulse Fourier-Transform mm-wave spectroscopy in a pulsed quasi-uniform flow excited state dynamics through the fairly deviation of the spectral (CPUF). This approach utilizes broadband microwave spectroscopy to extract line position, intensity anomaly and the change of the spectral linewidth. In this study, we have observed the rotationally- isomer-specific branching with MHz resolution and near-universal detection, coupled with resolved high-resolution fluorescence excitation spectra of the Figure 1. Fluorene 1 1 the well-defined low-temperature and high number densities afforded by a hybrid S1 B2←S0 A1 transition for fluorene. The magnetic effect was also measured up to 1.2 T to consider the excited state dynamics. supersonic flow. This is a quasi-uniform supersonic flow that we have identified and A molecular beam was obtained by expanding of Fluorene vapor with Ar gas through a pulsed nozzle into the vacuum chamber and collimated by using a skimmer and slit. Sub-Doppler characterized as an ideal environment in which to make chirped-pulse FTMW fluorescence excitation spectra were measured by crossing a single-mode UV laser beam measurements. The propargyl radical (C3H3) is produced by the 193nm photodissociation perpendicular to a collimated molecular beam. Absolute wavenumber was calibrated with accuracy 0.0002 cm-1 by measuring the Doppler-free saturation spectrum of iodine and a fringe pattern of the of 1,2-butadiene and other precursors. Upon absorption of a second photon at this same stabilized etalon. wavelength, H atom loss gives rise to three C H isomers: c-C H (cyclopropenylidene), Rotationally-resolved high-resolution fluorescence excitation spectra of 0-0 band and six 3 2 3 2 -1 1 3 vibronic bands have been observed in the region of 33770-35000 cm region. The typical linewidth l-C3H2 (propadienylidene), and HCCCH (propargylene). In this work, the branching is about 25 MHz which include the natural linewidth 10 MHz obtained from the reported 1 between these three channels is determined by direct measurement of c-C H and l-C H . lifetime15.6 ns. [1] The observed band were assigned as the a-type transition (selection rule: ∆K=0, 3 2 3 2 ∆J=0, ±1) from the spectral pattern. For the 0-0 band, 2489 lines were assigned, and their molecular In addition to their respective low-temperature branching fractions, their unique constants were determined with high accuracy. The obtained molecular constants are good agreement with the reported ones. [2] The observed rotational lines of the other vibronic bands were time-dependent behavior is also captured by the CPUF approach. also assigned and determined their molecular constants, but some bands show the difficulty of the 0 -1 rotational assignment. Especially, the typical energy shift was found for the 00 + 204 cm band due to the local perturbation with another vibronic level in S1 state.

[1] A. R. Auty, A. C. Jones and D. Phillips, J. Chem. Soc., Faraday Trans. 2, 82, 1219 (1986) . [2] J. T. Yi, L. Alvarez-Valtierra and D. W. Pratt, J. Chem. Phys. 124, 244302 (2006) .

126 129127 B32

Full observation of cascaded radiationless transitions from  S2( ) state of pyrazine by ultrafast VUV photoelectron imaging

Takuya Horio, and Toshinori Suzuki

Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan

A photoexcited molecule undergoes a variety of photophysical and photochemical processes simultaneously or sequentially, and the molecule ultimately relaxes to the ground electronic state or undergoes chemical reactions. Time-resolved photoelectron imaging (TRPEI) [1] enables full observation of these photo-induced dynamics, because photoionization can be induced from any part of the potential energy surfaces (PESs). However, photoionization from low-lying excited states and the ground electronic state requires high probe photon energy in the vacuum ultraviolet (VUV) wavelength region, and it was difficult to generate intense femtosecond VUV laser pulses. We have developed filamentation four-wave mixing (FWM) in rare gas [2,3] for routine generation of sub-20 fs VUV pulses, and we applied TRPEI using 9.3 eV probe photon to the benchmark system of pyrazine (C4N2H4) [4]. * ,We have excited jet-cooled pyrazine molecules into the S2(ππ ) state with 4.7-eV deep UV pulses and observed subsequent electronic dephasing processes by single photon ionization using 9.3-eV VUV pulses. As seen in Fig. 1, photoelectron image dramatically changes with the pump-probe delay times. * As we previously demonstrated [5], S2(ππ ) undergoes internal conversion to S1(n*) within 22 fs, while the * present study revealed that vibrationally-hot S1(nπ ) * further decays with 14.8 ps into S0 and T1(nπ ). * Additionally, configuration interaction of S2(ππ ) state was clearly observed via photoionization into multiple cationic states (Fig. 2).

Fig. 1 2D slices through the 3D photoelectron scattering * Fig. 2 (a) Photoelectron spectrum of S2( ). distributions obtained at (a) 1, (b) 25, (c) 49, (d) 1000, (e) (b) Electronic configurations for S (*) and 10000, and (f) 80000 fs. 2 cationic states.

References [1 ] T. Suzuki, Annu. Rev. Phys. Chem. 57, 555 (2006). [2] T. Horio, R. Spesyvtsev, and T. Suzuki, Opt. Express 21, 22423 (2013). [3 ] T. Horio, R. Spesyvtsev, and T. Suzuki, Opt. Lett. 39, 6021 (2014). [4] T. Horio et al. J. Chem. Phys. 145, 044306 (2016). [5] T. Horio, T. Fuji, Y.-I. Suzuki, and T. Suzuki, J. Am. Chem. Soc. 131, 10392 (2009).

130128

Full observation of cascaded radiationless transitions from [Note]  S2( ) state of pyrazine by ultrafast VUV photoelectron imaging

Takuya Horio, and Toshinori Suzuki

Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan

A photoexcited molecule undergoes a variety of photophysical and photochemical processes simultaneously or sequentially, and the molecule ultimately relaxes to the ground electronic state or undergoes chemical reactions. Time-resolved photoelectron imaging (TRPEI) [1] enables full observation of these photo-induced dynamics, because photoionization can be induced from any part of the potential energy surfaces (PESs). However, photoionization from low-lying excited states and the ground electronic state requires high probe photon energy in the vacuum ultraviolet (VUV) wavelength region, and it was difficult to generate intense femtosecond VUV laser pulses. We have developed filamentation four-wave mixing (FWM) in rare gas [2,3] for routine generation of sub-20 fs VUV pulses, and we applied TRPEI using 9.3 eV probe photon to the benchmark system of pyrazine (C4N2H4) [4]. * ,We have excited jet-cooled pyrazine molecules into the S2(ππ ) state with 4.7-eV deep UV pulses and observed subsequent electronic dephasing processes by single photon ionization using 9.3-eV VUV pulses. As seen in Fig. 1, photoelectron image dramatically changes with the pump-probe delay times. * As we previously demonstrated [5], S2(ππ ) undergoes internal conversion to S1(n*) within 22 fs, while the * present study revealed that vibrationally-hot S1(nπ ) * further decays with 14.8 ps into S0 and T1(nπ ). * Additionally, configuration interaction of S2(ππ ) state was clearly observed via photoionization into multiple cationic states (Fig. 2).

Fig. 1 2D slices through the 3D photoelectron scattering * Fig. 2 (a) Photoelectron spectrum of S2( ). distributions obtained at (a) 1, (b) 25, (c) 49, (d) 1000, (e) (b) Electronic configurations for S (*) and 10000, and (f) 80000 fs. 2 cationic states.

References [1] T. Suzuki, Annu. Rev. Phys. Chem. 57, 555 (2006). [2] T. Horio, R. Spesyvtsev, and T. Suzuki, Opt. Express 21, 22423 (2013). [3 ] T. Horio, R. Spesyvtsev, and T. Suzuki, Opt. Lett. 39, 6021 (2014). [4] T. Horio et al. J. Chem. Phys. 145, 044306 (2016). [5] T. Horio, T. Fuji, Y.-I. Suzuki, and T. Suzuki, J. Am. Chem. Soc. 131, 10392 (2009).

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[Note]

132 [Note]

133 [Note]

134 [Note]

135 International Advisory Committee

Evan Bieske (Australia)

Piergiorgio Casavecchia (Italy)

David Chandler (USA)

Reginald Colin (Belgium)

Robert Continetti (USA)

Robert Curl (USA)

Lauri Halonen (Finland)

Eizi Hirota (Japan)

Scott Kable (Australia)

Mats Larsson (Sweden)

Sydney Leach (France)

Yuan-Pern Lee (Taiwan)

John Maier (Switzerland)

Anthony Merer (Canada)

Hans ter Meulen (Netherlands)

Terry Miller (USA)

David Osborn (USA)

Timothy Steimle (USA)

Craig Taatjes (USA)

Friedrich Temps (Germany)

Brian A. Thrush (UK)

136130 International Advisory Committee Local Organizers

Evan Bieske (Australia) Organizers

Piergiorgio Casavecchia (Italy) Toshinori Suzuki (Kyoto University)

David Chandler (USA) Yasuhiro Ohshima (Tokyo Institute of Technology) Koichi Tsukiyama (Tokyo University of Science) Reginald Colin (Belgium)

Robert Continetti (USA)

Robert Curl (USA) Organizing staff members

Lauri Halonen (Finland) Shunsuke Adachi (Kyoto University) Takuya Horio (Kyoto University) Eizi Hirota (Japan) Kenta Mizuse (Tokyo Institute of Technology) Scott Kable (Australia) Junichi Nishitani (Kyoto University) Mats Larsson (Sweden) Takahiro Oyama (Tokyo University of Science) Sydney Leach (France) Stephan Thürmer (Kyoto University) Yuan-Pern Lee (Taiwan)

John Maier (Switzerland) Local advisory committee Anthony Merer (Canada) Mitsunori Araki (Tokyo University of Science) Hans ter Meulen (Netherlands) Masaru Fukushima (Hiroshima City University) Terry Miller (USA) Kensuke Harada (Kyushu University)

David Osborn (USA) Takashi Imajo (Japan Women’s University)

Timothy Steimle (USA) Haruki Ishikawa (Kitasato University) Hideto Kanamori (Tokyo Institute of Technology) Craig Taatjes (USA) Shunji Kasahara (Kobe University) Friedrich Temps (Germany) Kaori Kobayashi (Toyama University) Brian A. Thrush (UK) Hiroshi Kohguchi (Hiroshima University) Yoshihiro Sumiyoshi (Gunma University)

130 137 INDEX

A Shunsuke ADACHI B03 ······················· 101 Yuan-pern LEE S-10 ························31 Josep ANGLADA H-07, A28 ···········38, 88 Marsha LESTER S-09, A30 ···········30, 90 Mitsunori ARAKI A27 ························87 Jim LIN B11 ······················· 109 B Nadia BALUCANI S-20 ························46 Kopin LIU S-13 ························36 Luis BAÑARES S-19 ························44 M Ken MCKENDRICK S-21 ························47 Bernadette BRODERICK B31 ······················· 129 Terry MILLER S-12, N-02 ··········34, 52 Alaina BROWN B18 ······················· 116 Jun MIYAZAKI A19 ························79 C Carlos CABEZAS A23, B08 ···········83, 106 Kenta MIZUSE H-04, B17 ·········29, 115 Bor-chen CHANG B21 ······················· 119 Yuxiang MO H-10 ·······················48 Wentao CHEN A22 ························82 N Masakazu NAKAJIMA A05 ························65 Majed CHERGUI S-18 ························43 Kento NISHIMURA A16 ························76 Yutaro CHIBA B04 ······················· 102 Junichi NISHITANI A13 ························73 Robert CONTINETTI B01 ·························99 O Takeshi OKA H-01, B28 ····20, 50, 126 D Gabriel DA SILVA S-17 ························41 Toshiaki OKABAYASHI B19 ······················· 117 John DOYLE S-04 ························22 Jos OOMENS S-05 ························24 E Wolfgang EISFELD N-03 ·······················53 David OSBORN A01 ························61 Shinichi ENAMI H-05 ·······················32 Andreas OSTERWALDER H-02 ·······················23 Tomoya ENDO A06 ························66 Takahiro OYAMA B05 ······················· 103 F Christa FITTSCHEN H-08, B23 ·········42, 121 P Simon PURCELL B12 ······················· 110 Asuka FUJII S-11 ························33 Q Junting QIU B20 ······················· 118 Masaru FUKUSHIMA N-05, B15 ·········55, 113 R Matti RISSANEN A24 ························84 Mizuho FUSHITANI A09 ························69 S Nami SAKAI S-02 ························19 G Hua GUO S-14 ························37 Yosuke SAKAMOTO B25 ······················· 123 H Lauri HALONEN H-03, B29 ·········26, 127 Mayank SARASWAT B06 ······················· 104 Satoshi HAMANO A26 ························86 Hiroyuki SASADA A31 ························91 Karolina HAUPA B14 ······················· 112 Stephan SCHLEMMER S-06 ························25 Xucheng HE A12 ························72 Myles SCOLLON A20 ························80 Eizi HIROTA N-06 ·······················56 Leonid SHEPS S-16 ························40 Takuya HORIO H-09, B32 ·········45, 130 Anna STANCZAK A04 ························64 Shoma HOSHINO A02 ························62 Arthur SUITS S-08 ························28 I Hyotcherl IHEE S-07 ························27 Erin SULLIVAN A10 ························70 Haruki ISHIKAWA A25 ························85 Yoshihiro SUMIYOSHI A17 ························77 Siddharth IYER B10 ······················· 108 Bálint SZTÁRAY A32 ························92 K Scott KABLE A15 ························75 T Kohei TADA B13 ······················· 111 Hideto KANAMORI A03 ························63 Kaito TAKAHASHI B27 ······················· 125 Shutaro KARASHIMA A18 ························78 Shuro TAKANO A07 ························67 Shunji KASAHARA N-01, B30 ·········51, 128 Richard THOMAS A33 ························93 Wataru KASHIHARA B16 ······················· 114 Adam TREVITT B26 ······················· 124 Tatsuhiko KASHIMURA B02 ······················· 100 František TUREČEK H-06 ·······················35 Alireza KHARAZMI A08 ························68 V Sebastiaan VAN DE MEERAKKER S-03 ························21 Kaori KOBAYASHI A29 ························89 Y Koichi YAMADA N-04 ·······················54 Hiroshi KOHGUCHI B07 ······················· 105 Yo-ichi YAMAMOTO B22 ······················· 120 Nanase KOHNO B24 ······················· 122 Xueming YANG S-15 ························39 Nobuhiko KUZE A11 ························71 Emi YUDA A14 ························74 L Mats LARSSON A21 ························81 Z Jingsong ZHANG B09 ······················· 107 Sébastien LE PICARD S-01 ························18

138