On an EUV Atmospheric Simulation Chamber to Study the Photochemical Processes of Titan's Atmosphere
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
High-Resolution Infrared Spectroscopy: Jet-Cooled Halogenated Methyl Radicals and Reactive Scattering Dynamics in an Atom + Polyatom System
HIGH-RESOLUTION INFRARED SPECTROSCOPY: JET-COOLED HALOGENATED METHYL RADICALS AND REACTIVE SCATTERING DYNAMICS IN AN ATOM + POLYATOM SYSTEM by ERIN SUE WHITNEY B.A., Williams College, 1996 A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirement for the degree of Doctor of Philosophy Department of Chemistry and Biochemistry 2006 UMI Number: 3207681 Copyright 2006 by Whitney, Erin Sue All rights reserved. UMI Microform 3207681 Copyright 2006 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, MI 48106-1346 This thesis for the Doctor of Philosophy degree entitled: High resolution infrared spectroscopy: Jet cooled halogenated methyl radicals and reactive scattering dynamics in an atom + polyatom system written by Erin Sue Whitney has been approved for the Department of Chemistry and Biochemistry by David J. Nesbitt Veronica M. Bierbaum Date ii Whitney, Erin S. (Ph.D., Chemistry) High-Resolution Infrared Spectroscopy: Jet-cooled halogenated methyl radicals and reactive scattering dynamics in an atom + polyatomic system Thesis directed by Professor David J. Nesbitt. This thesis describes a series of projects whose common theme comprises the structure and internal energy distribution of gas-phase radicals. In the first two projects, shot noise-limited direct absorption spectroscopy is combined with long path-length slit supersonic discharges to obtain first high-resolution infrared spectra for jet-cooled CH2F and CH2Cl in the symmetric and antisymmetric CH2 stretching modes. -
Bimolecular Reaction Dynamics in the Phenyl - Silane System
Bimolecular Reaction Dynamics in the Phenyl - Silane System: Exploring the Prototype of a Radical Substitution Mechanism 1 1 1 1 2 Michael Lucas , Aaron M. Thomas , Tao Yang , Ralf I. Kaiser *, Alexander M. Mebel , Diptarka Hait3, Martin Head-Gordon3,4* 1 Department of Chemistry, University of Hawai’i at Manoa, Honolulu, HI 96822 2 Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 3 Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, CA 94720 4 Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 *Email: [email protected] *Email: [email protected] Abstract We present a combined experimental and theoretical investigation of the bimolecular gas phase reaction of the phenyl radical (C6H5) with silane (SiH4) under single collision conditions to investigate the chemical dynamics of forming phenylsilane (C6H5SiH3) via a bimolecular radical substitution mechanism at a tetra-coordinated silicon atom. Verified by electronic structure and quasiclassical trajectory calculations, the replacement of a single carbon atom in methane by silicon lowers the barrier to substitution thus defying conventional wisdom that tetra-coordinated hydrides undergo preferentially hydrogen abstraction. This reaction mechanism provides funda- mental insights into the hitherto unexplored gas phase chemical dynamics of radical substitution reactions of mononuclear main group hydrides under single collision conditions and highlights -
Thermochemical Properties of Methyl and Chloro-Methyl Hyplochlorites and Ethers and Reaction of Methyl Radical with CLO
New Jersey Institute of Technology Digital Commons @ NJIT Theses Electronic Theses and Dissertations Spring 5-31-2000 Thermochemical properties of methyl and chloro-methyl hyplochlorites and ethers and reaction of methyl radical with CLO Dawoon Jung New Jersey Institute of Technology Follow this and additional works at: https://digitalcommons.njit.edu/theses Part of the Chemistry Commons Recommended Citation Jung, Dawoon, "Thermochemical properties of methyl and chloro-methyl hyplochlorites and ethers and reaction of methyl radical with CLO" (2000). Theses. 778. https://digitalcommons.njit.edu/theses/778 This Thesis is brought to you for free and open access by the Electronic Theses and Dissertations at Digital Commons @ NJIT. It has been accepted for inclusion in Theses by an authorized administrator of Digital Commons @ NJIT. For more information, please contact [email protected]. Copyright Warning & Restrictions The copyright law of the United States (Title 17, United States Code) governs the making of photocopies or other reproductions of copyrighted material. Under certain conditions specified in the law, libraries and archives are authorized to furnish a photocopy or other reproduction. One of these specified conditions is that the photocopy or reproduction is not to be “used for any purpose other than private study, scholarship, or research.” If a, user makes a request for, or later uses, a photocopy or reproduction for purposes in excess of “fair use” that user may be liable for copyright infringement, This institution reserves -
Carbon Kinetic Isotope Effect in the Oxidation of Methane by The
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 95, NO. D13, PAGES 22,455-22,462, DECEMBER 20, 1990 CarbonKinetic IsotopeEffect in the Oxidationof Methaneby the Hydroxyl Radical CttRISTOPHERA. CANTRELL,RICHARD E. SHE•, ANTHONY H. MCDANmL, JACK G. CALVERT, JAMESA. DAVIDSON,DAVID C. LOWEl, STANLEYC. TYLER,RALPH J. CICERONE2, AND JAMES P. GREENBERG AtmosphericKinetics and PhotochemistryGroup, AtmosphericChemistry Division, National Centerfor AtmosphericResearch, Boulder, Colorado The reactionof the hydroxylradical (HO) with the stablecafix)n isotopes of methanehas been studied as a functionof temperaturefrom 273 to 353 K. The measuredratio of the rate coefficientsfor reaction with•ZCHn relative to •3CH•(kn•/kn3) was 1.0054 (20.0009 at the95% confidence interval), independent of temperaturewithin the precisionof the measurement,over the rangestudied. The precisionof the present valueis muchimproved over that of previousstudies, and this resultprovides important constraints on the currentunderstanding of the cyclingof methanethrough the atmospherethrough the useof carbonisotope measurements. INTRODUCTION weightedaverage of the sourceratios must equal the atmospher- Methane (CH•) is an importanttrace gas in the atmosphere ic ratio, after correctionfor fractionationin any lossprocesses. [Wofsy,1976]. It is a key sink for the tropospherichydroxyl The primaryloss of CI-I4in the troposphereis the reactionwith radical. Methane contributesto greenhousewarming [Donner the hydroxylradical: and Ramanathan,1980]; its potentialwarming effects follow only CO2 and H20. Methaneis a primary sink for chlorine (R1) CHn + HO ---)CH3 + HzO atomsin the stratosphereand a majorsource of watervapor in the upper stratosphere. The concentrationof CI-I4 in the The rate coefficient for this reaction has been studied extensive- tropospherehas been increasing at a rateof approximately1% ly (seereview by Ravishankara[1988]), but dataindicating the per year, at leastover the pastdecade [Rasmussen and Khalil, effect of isotopesubstitution in methaneare scarce. -
Gas-Phase Chemistry of Methyl-Substituted Silanes in a Hot-Wire Chemical Vapour Deposition Process
University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2013-08-27 Gas-phase Chemistry of Methyl-Substituted Silanes in a Hot-wire Chemical Vapour Deposition Process Toukabri, Rim Toukabri, R. (2013). Gas-phase Chemistry of Methyl-Substituted Silanes in a Hot-wire Chemical Vapour Deposition Process (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/26257 http://hdl.handle.net/11023/891 doctoral thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Gas-phase Chemistry of Methyl-Substituted Silanes in a Hot-wire Chemical Vapour Deposition Process by Rim Toukabri A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF CHEMISTRY CALGARY, ALBERTA August, 2013 © Rim Toukabri 2013 Abstract The primary decomposition and secondary gas-phase reactions of methyl- substituted silane molecules, including monomethylsilane (MMS), dimethylsilane (DMS), trimethylsilane (TriMS) and tetramethylsilane (TMS), in hot-wire chemical vapour deposition (HWCVD) processes have been studied using laser ionization methods in combination with time of flight mass spectrometry (TOF-MS). For all four molecules, methyl radical formation and hydrogen molecule formation have been found to be the common decomposition steps on both tungsten (W) and tantalum (Ta) filaments. -
A Photoionization Reflectron Time‐Of‐Flight Mass Spectrometric
Articles ChemPhysChem doi.org/10.1002/cphc.202100064 A Photoionization Reflectron Time-of-Flight Mass Spectrometric Study on the Detection of Ethynamine (HCCNH2) and 2H-Azirine (c-H2CCHN) Andrew M. Turner,[a, b] Sankhabrata Chandra,[a, b] Ryan C. Fortenberry,*[c] and Ralf I. Kaiser*[a, b] Ices of acetylene (C2H2) and ammonia (NH3) were irradiated with 9.80 eV, and 10.49 eV were utilized to discriminate isomers energetic electrons to simulate interstellar ices processed by based on their known ionization energies. Results indicate the galactic cosmic rays in order to investigate the formation of formation of ethynamine (HCCNH2) and 2H-azirine (c-H2CCHN) C2H3N isomers. Supported by quantum chemical calculations, in the irradiated C2H2:NH3 ices, and the energetics of their experiments detected product molecules as they sublime from formation mechanisms are discussed. These findings suggest the ices using photoionization reflectron time-of-flight mass that these two isomers can form in interstellar ices and, upon spectrometry (PI-ReTOF-MS). Isotopically-labeled ices confirmed sublimation during the hot core phase, could be detected using the C2H3N assignments while photon energies of 8.81 eV, radio astronomy. 1. Introduction acetonitrile (CH3CN; 1) and methyl isocyanide (CH3NC; 2) ‘isomer doublet’ (Figure 2) – the methyl-substituted counterparts of For the last decade, the elucidation of the fundamental reaction hydrogen cyanide (HCN) and hydrogen isocyanide (HNC) – has pathways leading to structural isomers – molecules with the been detected toward the star-forming region SgrB2.[4,8–9] same molecular formula, but distinct connectivities of atoms – However, none of their higher energy isomers has ever been of complex organic molecules (COMs) in the interstellar identified in any astronomical environment: 2H-azirine (c- [10–14] [15–19] medium (ISM) has received considerable interest from the NCHCH2; 3), ethynamine (HCCNH2; 4), ketenimine [1–3] [20] [21] astrochemistry and physical chemistry communities. -
The Distribution of the Hydroxyl Radical in the Troposphere Jack
The Distribution of the Hydroxyl Radical in the Troposphere By Jack Fishman Paul J. Crutzen Department of Atmospheric Science Colorado State University Fort Collins, Colorado THE DISTRIBUTION OF THE HYDROXYL RADICAL IN THE TROPOSPHERE by Jack Fishman and Paul J. Crutzen Preparation of this report has been financially supported by Environmental Protection Agency Grant No. R80492l-0l Department of Atmospheric Science Colorado State University Fort Collins, Colorado January, 1978 Atmospheric Science Paper No. 284 Abstract A quasi-steady state photochemical numerical model is developed to calculate a two-dimensional distribution of the hydroxyl (OH) radical in the troposphere. The diurnally, seasonally averaged globaJ 5 3 value of OH derived by this model is 3 x 10 cm- which is several times lower than the number computed previously by other models, but is in good agreement with the value inferred from the analysis of the tropospheric distribution of methyl chloroform. Likewise, the effects of the computed OH distribution on the tropospheric budgets of ozone and carbon monoxide are not inconsistent with this lower computed value. One important result of this research is the detailed analysis of the distribution of tropospheric ozone in the Southern Hemisphere. Our work shows that there is a considerable difference in the tropospheric ozone patterns of the two hemispheres and that through the analysis of the likely photochemistry occurring in the troposphere, a significant source of tropospheric ozone may exist in the Northern Hemisphere due to carbon monoxide oxidation. Future research efforts will be devoted to the meteorological dynamics of the two hemispheres to try to distinguish if these physical processes are similarly able to explain the interhemispheric differences in tropospheric ozone. -
A Chemical Kinetics Network for Lightning and Life in Planetary Atmospheres P
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by St Andrews Research Repository The Astrophysical Journal Supplement Series, 224:9 (33pp), 2016 May doi:10.3847/0067-0049/224/1/9 © 2016. The American Astronomical Society. All rights reserved. A CHEMICAL KINETICS NETWORK FOR LIGHTNING AND LIFE IN PLANETARY ATMOSPHERES P. B. Rimmer and Ch Helling School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK; [email protected] Received 2015 June 3; accepted 2015 October 22; published 2016 May 23 ABSTRACT There are many open questions about prebiotic chemistry in both planetary and exoplanetary environments. The increasing number of known exoplanets and other ultra-cool, substellar objects has propelled the desire to detect life andprebiotic chemistry outside the solar system. We present an ion–neutral chemical network constructed from scratch, STAND2015, that treats hydrogen, nitrogen, carbon, and oxygen chemistry accurately within a temperature range between 100 and 30,000 K. Formation pathways for glycine and other organic molecules are included. The network is complete up to H6C2N2O3. STAND2015 is successfully tested against atmospheric chemistry models for HD 209458b, Jupiter, and the present-day Earth using a simple one- dimensionalphotochemistry/diffusion code. Our results for the early Earth agree with those of Kasting for CO2,H2, CO, and O2, but do not agree for water and atomic oxygen. We use the network to simulate an experiment where varied chemical initial conditions are irradiated by UV light. The result from our simulation is that more glycine is produced when more ammonia and methane is present. -
A Variationally Computed IR Line List for the Methyl Radical CH3 Arxiv
A Variationally Computed IR Line List for the Methyl Radical CH3 Ahmad Y. Adam,y Andrey Yachmenev,z Sergei N. Yurchenko,{ and Per Jensen∗,y yFakult¨atf¨urMathematik und Naturwissenschaften, Physikalische und Theoretische Chemie, Bergische Universit¨atWuppertal, D{42097 Wuppertal, Germany zCenter for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607 Hamburg, Germany, The Hamburg Center for Ultrafast Imaging, Universit¨atHamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany {Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom E-mail: [email protected] arXiv:1905.05504v1 [physics.chem-ph] 14 May 2019 1 Abstract We present the first variational calculation of a hot temperature ab initio line list for the CH3 radical. It is based on a high level ab initio potential energy surface and dipole moment surface of CH3 in the ground electronic state. The ro-vibrational energy lev- els and Einstein A coefficients were calculated using the general-molecule variational approach implemented in the computer program TROVE. Vibrational energies and vibrational intensities are found to be in very good agreement with the available ex- perimental data. The line list comprises 9,127,123 ro-vibrational states (J ≤ 40) and 2,058,655,166 transitions covering the wavenumber range up to 10000 cm−1 and should be suitable for temperatures up to T = 1500 K. Introduction The methyl radical CH3 is a free radical of major importance in many areas of science such as hydrocarbon combustion processes,1 atmospheric chemistry,2 the chemistry of semiconductor production,3 the chemical vapor deposition of diamond,4 and many chemical processes of current industrial and environmental interest. -
Directed Gas Phase Formation of Silicon Dioxide and Implications for the Formation of Interstellar Silicates
ARTICLE DOI: 10.1038/s41467-018-03172-5 OPEN Directed gas phase formation of silicon dioxide and implications for the formation of interstellar silicates Tao Yang 1,2, Aaron M. Thomas1, Beni B. Dangi1,3, Ralf I. Kaiser 1, Alexander M. Mebel 4 & Tom J. Millar 5 1234567890():,; Interstellar silicates play a key role in star formation and in the origin of solar systems, but their synthetic routes have remained largely elusive so far. Here we demonstrate in a combined crossed molecular beam and computational study that silicon dioxide (SiO2) along with silicon monoxide (SiO) can be synthesized via the reaction of the silylidyne radical (SiH) with molecular oxygen (O2) under single collision conditions. This mechanism may provide a low-temperature path—in addition to high-temperature routes to silicon oxides in circum- stellar envelopes—possibly enabling the formation and growth of silicates in the interstellar medium necessary to offset the fast silicate destruction. 1 Department of Chemistry, University of Hawai’iatMānoa, Honolulu, HI 96822, USA. 2 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200062, China. 3 Department of Chemistry, Florida Agricultural and Mechanical University, Tallahassee, FL 32307, USA. 4 Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA. 5 Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN, UK. Correspondence and requests for materials should be addressed to R.I.K. (email: [email protected]) or to A.M.M. (email: mebela@fiu.edu) or to T.J.M. (email: [email protected]) NATURE COMMUNICATIONS | (2018) 9:774 | DOI: 10.1038/s41467-018-03172-5 | www.nature.com/naturecommunications 1 ARTICLE NATURE COMMUNICATIONS | DOI: 10.1038/s41467-018-03172-5 — 28 + 28 + he origin of interstellar silicate grains nanoparticles ( SiO2 ), and 44 ( SiO ). -
Product Detection of the CH Radical Reactions with Ammonia and Methyl-Substituted Amines Jérémy Bourgalais, Kacee L
Product Detection of the CH Radical Reactions with Ammonia and Methyl-Substituted Amines Jérémy Bourgalais, Kacee L. Caster, Olivier Durif, David L. Osborn, Sébastien D. Le Picard, Fabien Goulay To cite this version: Jérémy Bourgalais, Kacee L. Caster, Olivier Durif, David L. Osborn, Sébastien D. Le Picard, et al.. Product Detection of the CH Radical Reactions with Ammonia and Methyl-Substituted Amines. Journal of Physical Chemistry A, American Chemical Society, 2019, 123 (11), pp.2178-2193. 10.1021/acs.jpca.8b11688. hal-02089225 HAL Id: hal-02089225 https://hal-univ-rennes1.archives-ouvertes.fr/hal-02089225 Submitted on 11 Apr 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Page 1 of 47 The Journal of Physical Chemistry 1 2 3 Product Detection of the CH Radical Reactions with Ammonia and 4 5 6 Methyl-Substituted Amines 7 8 1 2 3 4 9 Jeremy Bourgalais, Kacee L. Caster, Olivier Durif, David L. Osborn, Sebastien D. Le 10 11 Picard,3 and Fabien Goulay2,* 12 13 1 LATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, 14 -
Condensed-Phase Photochemistry in the Absence of Radiation Chemistry Ella Mullikin
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Wellesley College Wellesley College Wellesley College Digital Scholarship and Archive Faculty Research and Scholarship 6-27-2018 Condensed-Phase Photochemistry in the Absence of Radiation Chemistry Ella Mullikin Pierce van Mulbregt Jeniffer Perea Muhammad Kasule Jean Huang See next page for additional authors Follow this and additional works at: https://repository.wellesley.edu/scholarship Version: Post-print Recommended Citation E. Mullikin, P. van Mulbregt, J. Perea, M. Kasule, J. Huang, C. Buffo, J. Campbell, L. Gates, H. M. Cumberbatch, Z. Peeler, H. Schneider, J. Lukens, S. T. Bao, R. Tano-Menka, S. Baniya, K. Cui, M. Thompson, A. Hay, L. Widdup, A. Caldwell-Overdier, J. Huang, M. C. Boyer, M. Rajappan, G. Echebiri and C. R. Arumainayagam, ACS Earth and Space Chemistry, 2018, DOI: 10.1021/ acsearthspacechem.8b00027. This Article is brought to you for free and open access by Wellesley College Digital Scholarship and Archive. It has been accepted for inclusion in Faculty Research and Scholarship by an authorized administrator of Wellesley College Digital Scholarship and Archive. For more information, please contact [email protected]. Authors Ella Mullikin, Pierce van Mulbregt, Jeniffer Perea, Muhammad Kasule, Jean Huang, Christina Buffo, Jyoti Campbell, Leslie Gates, Helen M. Cumberbatch, Zoe Peeler, Hope Schneider, Julia Lukens, Si Tong Bao, Rhoda Tano-Menka, Subha Baniya, Kendra Cui, Mayla Thompson, Aury Hay, Lily Widdup, Anna Caldwell- Overier, Justine Huang, Michael C. Boyer, Mahesh Rajappan, Geraldine Echebiri, and Christopher R. Arumainayagam This article is available at Wellesley College Digital Scholarship and Archive: https://repository.wellesley.edu/scholarship/183 Condensed-Phase Photochemistry in the Absence of Radiation Chemistry Ella Mullikin,1 Pierce van Mulbregt,2 Jeniffer Perea,1 Muhammad Kasule,3 Jean Huang,1 Christina Buffo,1 Jyoti Campbell,1 Leslie Gates,1 Helen M.