DOCSLIB.ORG

Book of Abstracts

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

THE PHYSICS AND CHEMISTRY OF THE INTERSTELLAR MEDIUM Celebrating the first 40 years of Alexander Tielens' contribution to Science Book of Abstracts Palais des Papes - Avignon - France 2-6 September 2019 CONFERENCE PROGRAM Monday 2 September 2019 Time Speaker 10:00 Registration 13:00 Registration & Welcome Coffee 13:30 Welcome Speech C. Ceccarelli Opening Talks 13:40 PhD years H. Habing 13:55 Xander Tielens and his contributions to understanding the D. Hollenbach ISM The Dust Life Cycle 14:20 Review: The dust cycle in galaxies: from stardust to planets R. Waters and back 14:55 The properties of silicates in the interstellar medium S. Zeegers 15:10 3D map of the dust distribution towards the Orion-Eridanus S. Kh. Rezaei superbubble with Gaia DR2 15:25 Invited Talk: Understanding interstellar dust from polariza- F. Boulanger tion observations 15:50 Coffee break 16:20 Review: The life cycle of dust in galaxies M. Meixner 16:55 Dust grain size distribution across the disc of spiral galaxies M. Relano 17:10 Investigating interstellar dust in local group galaxies with G. Clayton new UV extinction curves 17:25 Invited Talk: The PROduction of Dust In GalaxIES C. Kemper (PRODIGIES) 17:50 Unravelling dust nucleation in astrophysical media using a L. Decin self-consistent, non steady-state, non-equilibrium polymer nucleation model for AGB stellar winds 19:00 Dining Cocktail Tuesday 3 September 2019 08:15 Registration PDRs 09:00 Review: The atomic to molecular hydrogen transition: a E. Roueff major step in the understanding of PDRs 09:35 Invited Talk: The Orion Bar: from ALMA images to new J. Goicoechea dynamic PDR models 10:00 [CII] optical depth and self-absorption in M17SW C. Guevara 10:15 Coffee break & Posters 11:15 Review: PDRs near and far: the extraordinary utility of M. Kaufman photodissociation region models 1 Time Speaker 11:50 The importance of the atomic history in time-dependent M. de Avillez simulations of the interstellar gas- from non-thermal to ther- mal distributions 12:05 The physical state of CO-dark gas in the Perseus arm M. Busch 12:20 Lunch break & Posters 14:30 The low-metallicity ISM of dwarf galaxies: the multiphase S. Madden structure and the CO-dark gas 14:45 The atomic envelope of molecular clouds as revealed by ma- J.D. Soler chine vision PAH 15:00 Spectroscopy of interstellar polyaromatic hydrocarbons and J. Bouwman their photoproducts 15:15 Unravelling spectral signatures and photochemical processes A. Petrignani of polycyclic aromatic hydrocarbons 15:30 Coffee break & Posters 16:25 Tracing PAH size in prominent nearby mid-infrared environ- C. Knight ments 16:40 Radioastronomical observations of PAHs and other aromatic B. McGuire species at the earliest stages of star formation 16:55 Formation process of small hydrocarbons in PDRs: gas M. Tiwari phase chemistry or fragmentation of polycyclic aromatic hy- drocarbons (PAHs)? 17:10 Review: Today's PAH model: four not so easy pieces L. Allamandola Wednesday 4 September 2019 08:15 Registration PAH 09:00 Review: Astro-PAHs: a journey from space to the labora- C. Joblin tory 09:35 PAHs on/in water ice: structures, energetics, and spec- J. Mascetti tra from FTIR experiments and a multi-method theoretical study 09:50 Photoionization of polycyclic aromatic hydrocarbons: con- P. Br´echignac tribution to the heating of the Interstellar Medium 10:05 Invited talk: ISM spectra from near- to mid-infrared T. Onaka 10:30 Coffee break & Posters 11:35 Experimental studies of the catalytic role of oxygen func- R. Jaganathan tionalized PAHs Ices 11:50 Review: From simple to complex molecules in interstellar A. Boogert ices 12:25 Ices in small dense molecular cores L. Chu 12:40 Formation of molecules on cold interstellar grains F. Dulieu 12:55 Lunch break & Free afternoon 2 Thursday 5 September 2019 Time Speaker 08:15 Registration Ices 09:00 Review: From astrochemistry to astrobiology? A few se- L. d'Hendecourt lected papers on cosmic ices evolution 09:35 SPHEREx: surveying the milky way in biogenic ices G. Melnick 09:50 Adsorption of volatile molecules on interstellar car- B. Mate bonaceaous analogs 10:05 Invited talk: Laboratory investigations on the chemical and M.E. Palumbo optical properties of interstellar ice analogs 10:30 Coffee break & Posters 11:30 Quantum chemistry computations as an interpretative and A. Rimola predictive tool for grain-induced astrochemical processes. The formamide formation case 11:45 The physics and chemistry on the surface of cosmic dust A. Potapov grains + 12:00 H2 and HCO formation at the interface with crystalline S. Pantaleone models of icy mantles: insights from periodic DFT-MD sim- ulations 12:15 Damaged water ice: an opportunity for reactivity? A. Markovits 12:30 Lunch break & Posters Astrochemistry 14:30 Review: Carbon chemistry in evolved stars J. Cernicharo 15:05 Invited talk: Molecular complexity in solar-type star form- B. Lefloch ing regions 15:30 IRAM hunt for hot corino and WCCC objects in the OMC- M. Bouvier 2/3 filament 15:45 First astrophysical detection of the helium hydride ion HeH+ R. Guesten 16:00 Coffee break & Posters 17:00 Astrochemistry of protoplanetary disks from an observa- C. Favre tional point of view 17:15 Modelling of the chemistry of protoplanetary disks M. Ruaud 17:30 Chemistry and isotopic ratios in intermediate redhisft molec- S. Wallstrom ular absorbers 17:45 The effect of circumstellar dust grains on the gas phase M. Van De Sande chemistry in AGB outflows 20:00 Social dinner 21:30 After dinner speaker M. Wolfire 3 Friday 6 September 2019 Time Speaker 08:15 Registration Astrochemistry 09:00 Review: Gas-phase chemistry in the interstellar medium: N. Balucani there is still much to learn 09:35 Prevalent complex organic molecules towards prestellar S. Scibelli cores in the Taurus star forming region 09:50 Invited talk: Grain surface chemistry and its impact on the S. Cazaux gas phase 10:15 A computational study of the reaction N(2D)+C6H6: impli- D. Skouteris cations for the upper atmosphere of Titan 10:30 Coffee break & Posters Future & Perspectives 11:00 Review: Future developments of IRAM instruments K. Schuster 11:25 Review: Observing facilities for astrochemistry: evolution T. de Graauw and future perspectives 11:50 Review: Astrochemistry: the next 40 years E. van Dishoeck 12:15 Closing talk T. Millar 4 ORAL CONTRIBUTIONS 5 Today's PAH model: four not so easy pieces Louis Allamandola1∗y 1 BAERI, NASA Ames Research Center { United States Over the past thirty-five years the interstellar PAH hypothesis has been tested, has had predictions borne out, and has been successfully applied to a surprising number of disparate astrophysical and astrochemical processes. Along the way, the PAH hypothesis became the PAH model. This progress has only been possible thanks to the close collaboration between laboratory experimentalists, astronomers, modelers and theoreticians. Due to the deep interdisciplinarity of the "PAH Problem" however, this progress has been made in ’fits and starts', and often in choppy, unconnected steps with the result that today's model is not yet as fully integrated into a whole as it can be. Adding to the complexity, since astronomical PAHs are nano-sized molecules, not particles, they play astrophysical and astrochemical roles that differ from those of grains. Given the information PAH spectra contain about the astronomical objects in which they are found, and the key roles they are now called upon to play in the astrophysics of many (if not most) objects across the Universe, sharpening the model as much as it can be sharpened is key to its full exploitation as a novel and far-reaching astronomical tool. This is particularly critical now with the anticipated launch of the James Webb Space Telescope (JWST ) in about two years. JWST 's combination of unprecedented sensitivity, spectral resolution, and wavelength coverage will make it possible, for the first time, to measure and fully characterize PAH spectra across the complete 1 - 28 µm range, the range in which the strongest PAH fundamental bands and associated features fall. Interstellar PAH mid-IR emission spectra form the foundation on which the entire PAH model rests. While great progress has been made in understanding the general spectroscopy of such large molecules, very significant challenges regarding important spectroscopic details remain. Similarly with PAH growth and destruction. Until recently the stepwise processes invoked to grow simple molecules containing a few carbon atoms to polycyclic aromatic structures and fullerenes were very general. Now there are a number of experimental and theoretical studies that show generalizations do not capture PAH growth, destruction and evolution well. Likewise with more complex chemistry involving PAHs. The recent, exciting discovery of benzonitrile in the cold core TMC-1 is the tip of an iceberg. Pun intended. Over the past decade or two, sophisticated experimental work has revealed some of the steps involved in the growth and destruction of PAHs in the gas. This depth of understanding does not yet hold for interstellar ice chemistry involving PAHs. It is critically important to gain this knowledge because a number of laboratory studies of interstellar ice analogs and models show that the inclusion of PAHs can profoundly influence ice chemistry and physics. Taken together, these gaps in our detailed knowledge severely limit what astronomical PAHs tell us today versus what they can tell us. This talk will touch on some of the recent laboratory advances and challenges in four areas: PAH spectroscopy, growth, destruction, and chemistry. ∗Speaker yCorresponding author: [email protected] 6 Gas-phase chemistry in the interstellar medium: there is still much to learn Nadia Balucani1∗y 1 DCBB, Universit`adegli Studi di Perugia { Perugia, Italy After the \scoundrels rule" according to which the formation of hydrides is due to processes occurring on the surface of the icy mantles of interstellar grains [1], it has been proposed that the entire set of interstellar complex organic molecules is actually formed by radical-radical recom- bination processes assisted by interstellar ice [2]).
Recommended publications
  • UNITED STATES PATENT of FICE 1926,642 PROCESS of OBTAINING REACTION PRODUCTS of RETENE Charles O

    UNITED STATES PATENT of FICE 1926,642 PROCESS of OBTAINING REACTION PRODUCTS of RETENE Charles O

    Patented Sept. 12, 1933 1926,642 UNITED STATES PATENT of FICE 1926,642 PROCESS OF OBTAINING REACTION PRODUCTS OF RETENE Charles O. Young and George H. Reid, South Charleston, W. Wa, assignors to Carbide & Carbon Chemicals. Corporation, a corporation of New York No Drawing. Application December 2, 1930 Serial No. 502,005 8 Claims. (C. 260-06) The invention is an improved process of mak plied in any desired manner, for example the ap ing reaction products of ketene (CH2=C-O). In paratus for quenching the hot vapors may take general, the process of our invention comprises the form of a packed tower scrubber, spray-scrub thermally decomposing a substance which will ber or any other suitable means for rapidly cool form ketene, and rapidly cooling the hot gaseous ing the hot vapors in intimate contact with the 80 products of this pyrolysis in intimate contact with abSOrbing medium. a reacting absorbing medium. The absorption or quenching means may be The principal object of the invention is to pro operated at ordinary temperatures, and in such Wide a method of making ketene and reaction a case the resultant liquid will contain the reac 0 products thereof which will result in the forma tion product of ketene and the absorbing medium, 65 tion of a maximum amount of valuable product excess absorbing medium and condensed un and which will minimize losses of the ketene changed acetone. The liquid may be circulated formed. until Sufficiently reacted with ketene and then sep In the manufacture of ketene by the pyrolysis arated from the diluent acetone, or it may be oth 15 of organic compounds, e.g., acetone, two primary erwise treated for the separation or recovery of O difficulties in Securing useful quantities of ketene its several constituents.
  • Origin and Evolution of Carbonaceous Presolar Grains in Stellar Environments

    Origin and Evolution of Carbonaceous Presolar Grains in Stellar Environments

    Bernatowicz et al.: Origin and Evolution of Presolar Grains 109 Origin and Evolution of Carbonaceous Presolar Grains in Stellar Environments Thomas J. Bernatowicz Washington University Thomas K. Croat Washington University Tyrone L. Daulton Naval Research Laboratory Laboratory microanalyses of presolar grains provide direct information on the physical and chemical properties of solid condensates that form in the mass outflows from stars. This informa- tion can be used, in conjunction with kinetic models and equilibrium thermodynamics, to draw inferences about condensation sequences, formation intervals, pressures, and temperatures in circumstellar envelopes and in supernova ejecta. We review the results of detailed microana- lytical studies of the presolar graphite, presolar silicon carbide, and nanodiamonds found in primitive meteorites. We illustrate how these investigations, together with astronomical obser- vation and theoretical models, provide detailed information on grain formation and growth that could not be obtained by astronomical observation alone. 1. INTRODUCTION versed the interstellar medium (ISM) prior to their incorpor- ation into the solar nebula, they serve as monitors of physi- In recent years the laboratory study of presolar grains has cal and chemical processing of grains in the ISM (Bernato- emerged as a rich source of astronomical information about wicz et al., 2003). stardust, as well as about the physical and chemical condi- In this review we focus on carbonaceous presolar grains. tions of dust formation in circumstellar
  • Origins of Life: Transition from Geochemistry to Biogeochemistry

    Origins of Life: Transition from Geochemistry to Biogeochemistry

    December 2016 Volume 12, Number 6 ISSN 1811-5209 Origins of Life: Transition from Geochemistry to Biogeochemistry NITA SAHAI and HUSSEIN KADDOUR, Guest Editors Transition from Geochemistry to Biogeochemistry Staging Life: Warm Seltzer Ocean Incubating Life: Prebiotic Sources Foundation Stones to Life Prebiotic Metal-Organic Catalysts Protometabolism and Early Protocells pub_elements_oct16_1300&icpms_Mise en page 1 13-Sep-16 3:39 PM Page 1 Reproducibility High Resolution igh spatial H Resolution High mass The New Generation Ion Microprobe for Path-breaking Advances in Geoscience U-Pb dating in 91500 zircon, RF-plasma O- source Addressing the growing demand for small scale, high resolution, in situ isotopic measurements at high precision and productivity, CAMECA introduces the IMS 1300-HR³, successor of the internationally acclaimed IMS 1280-HR, and KLEORA which is derived from the IMS 1300-HR³ and is fully optimized for advanced U-Th-Pb mineral dating. • New high brightness RF-plasma ion source greatly improving spatial resolution, reproducibility and throughput • New automated sample loading system with motorized sample height adjustment, significantly increasing analysis precision, ease-of-use and productivity • New UV-light microscope for enhanced optical image resolution (developed by University of Wisconsin, USA) ... and more! Visit www.cameca.com or email [email protected] to request IMS 1300-HR³ and KLEORA product brochures. Laser-Ablation ICP-MS ~ now with CAMECA ~ The Attom ES provides speed and sensitivity optimized for the most demanding LA-ICP-MS applications. Corr. Pb 207-206 - U (238) Recent advances in laser ablation technology have improved signal 2SE error per sample - Pb (206) Combined samples 0.076121 +/- 0.002345 - Pb (207) to background ratios and washout times.
  • Nov 15, Ketene Chemistry and the Application in Synthesis by Xuan Zhou

    Nov 15, Ketene Chemistry and the Application in Synthesis by Xuan Zhou

    Ketene chemistry and the application in synthesis Dong group at UT Austin Xuan Zhou Nov 14, 2013 Ketene chemistry Content • A brief history of ketene • Type of ketenes • Ketene preparation • Ketenes in synthesis Reviews about ketenes: T. T. Tidwell, Ketenes, 2nd ed., wiley interscience, Hoboken, NJ, 2006. T. T. Tidwell, Eur. J. Org. Chem. 2006, 563-576. T. T. Tidwell, Angew. Chem. Int. Ed. 2005, 44, 5778-5785. A brief history of ketene The first reported ketene: Diphenylketene Wedekind Ketene and its Dimer: N.T.M. Wilsmore, J. Chem. Soc. 1907, 91, 1938 Asymmetric reactions of ketene: H. Pracejus, Justus liebigs Ann. Chem. 1969, 722, 1-11 Bisketenes First prepared bisketenes by Wolf in 1906 O. Diels, B. Wolf, Ber. Dtsch. Chem. Ges. 1906, 39, 689-697 First observed bisketenes in 1982 G. Maier, H. P. Reisenauer, T. Sayrac, Chem. Ber. 1982, 115, 2192 Substituent effects of ketene Melvin Newman Shchukovskaya Cycloadditions of ketenes Lee Irvin Smith Derek H.R. Barton Angew. Chem. Int. Ed. 2005, 44, 5779-5785 Type of ketenes Carbon-substituted ketenes • Alkylketenes 2 3 4 • Alkenylketenes 5 6 7 • alkynylketenes and cyanoketenes 8 9 10 Type of ketenes • Arylketenes 1 2 3 • Acylketenes 4 5 6 • Imidoylketenes 7 azetinones 8 Nitrogen-substituted ketenes 1 Nitroketene Azidoketene Isocyanatoketene 2 Oxygen-substituted ketenes 3 4 5 6 Halogen-substituted ketenes 1 2 3 4 Silyl-ketenes 5 6 7 Phosphorous, sulfur, metal-substituted and bis ketenes 1 2 5 6 7 8 9 10 11 12 Ketene preparation Ketenes from ketene dimers •Pyrolysis of ketene dimer 1 2 3 4 •Photolysis
  • The Interactions and Reactions of Atoms and Molecules on the Surfaces of Model Interstellar Dust Grains

    The Interactions and Reactions of Atoms and Molecules on the Surfaces of Model Interstellar Dust Grains

    The Interactions and Reactions of Atoms and Molecules on the Surfaces of Model Interstellar Dust Grains A thesis submitted for the degree of Doctor of Philosophy Helen Jessica Kimber Department of Chemistry University College London 2016 -I, Helen Jessica Kimber, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. Signed, i Abstract The elemental composition of the known universe comprises almost exclusively light atoms (~99.9% hydrogen and helium). However, to date, close to 200 different molecules have been detected in the interstellar medium (ISM) where their distribution is far from uniform. The vast majority of these molecules are contained within vast clouds of gas and dust referred to as interstellar clouds. Within these interstellar clouds, many of the molecules present are formed via gas-phase ion-neutral reactions. However, there are several molecules for which known gas-phase kinetics cannot account for observed gas-phase abundances. As a result, reactions occurring on the surface of interstellar dust grains are invoked to account for the observed abundances of some of these molecules. This thesis presents results of experimental investigations into the interaction and reactions of atoms and molecules on the surface of model interstellar dust grains. Chapters three and four present results for the reaction of (3P)O on molecular ices. Specifically, the reaction of (3P)O and propyne or acrylonitrile. After a one hour dosing period, temperature programmed desorption (TPD), coupled with time-of-flight mass spectrometry (TOFMS), are used to identify (3P)O addition products.
  • Lifetimes of Interstellar Dust from Cosmic Ray Exposure Ages of Presolar Silicon Carbide

    Lifetimes of Interstellar Dust from Cosmic Ray Exposure Ages of Presolar Silicon Carbide

    Lifetimes of interstellar dust from cosmic ray exposure ages of presolar silicon carbide Philipp R. Hecka,b,c,1, Jennika Greera,b,c, Levke Kööpa,b,c, Reto Trappitschd, Frank Gyngarde,f, Henner Busemanng, Colin Madeng, Janaína N. Ávilah, Andrew M. Davisa,b,c,i, and Rainer Wielerg aRobert A. Pritzker Center for Meteoritics and Polar Studies, The Field Museum of Natural History, Chicago, IL 60605; bChicago Center for Cosmochemistry, The University of Chicago, Chicago, IL 60637; cDepartment of the Geophysical Sciences, The University of Chicago, Chicago, IL 60637; dNuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550; ePhysics Department, Washington University, St. Louis, MO 63130; fCenter for NanoImaging, Harvard Medical School, Cambridge, MA 02139; gInstitute of Geochemistry and Petrology, ETH Zürich, 8092 Zürich, Switzerland; hResearch School of Earth Sciences, The Australian National University, Canberra, ACT 2601, Australia; and iEnrico Fermi Institute, The University of Chicago, Chicago, IL 60637 Edited by Mark H. Thiemens, University of California San Diego, La Jolla, CA, and approved December 17, 2019 (received for review March 15, 2019) We determined interstellar cosmic ray exposure ages of 40 large ago. These grains are identified as presolar by their large isotopic presolar silicon carbide grains extracted from the Murchison CM2 anomalies that exclude an origin in the Solar System (13, 14). meteorite. Our ages, based on cosmogenic Ne-21, range from 3.9 ± Presolar stardust grains are the oldest known solid samples 1.6 Ma to ∼3 ± 2 Ga before the start of the Solar System ∼4.6 Ga available for study in the laboratory, represent the small fraction ago.
  • Hollenbach D CV2008.Pdf

    Hollenbach D CV2008.Pdf

    SUMMARY CURRICULUM VITA DAVID JOHN HOLLENBACH Education: PhD., Theoretical Physics, Cornell University, 1969 Present Area of Research: Theoretical astrophysics, infrared astronomy, interstellar medium, star formation, astrochemistry, astrobiology Professional Activities: Senior member of American Astronomical Society, Senior member of International Astronomical Union, Study Scientist Large Deployable Telescope (LDR) Project (1980-84), Member of NASA Astronomy and Relativity Management Operation Working Group (ARMOWG) (1985-88), Scientific Organizing Committee for IAU Symposium 120, “Astrochemistry” (1984-85), Scientific Organizing Committee for Summer Schools on "Interstellar Processes”, The Interstellar Medium of Galaxies", and "The Evolution of Galaxies and Their Environment" (1985-1992), Director (PI) of the Center for Star Formation Studies, a consortium of NASA-Ames, UC Berkeley, and UC Santa Cruz Theoretical Astrophysicists funded by the NASA Theory Program (1985-2002), Member of the Executive Committee for the Space Sciences Laboratory, UC Berkeley (1985-1995), Co-Investigator on the Submillimeter Wave Astronomical Satellite (SWAS)(1988-present), Member of the Infrared Panel of the National Academy of Sciences Astronomy Astrophysics Survey Committee(1988-1990), Member of the ISO Short Wavelength Spectrometer Team (1990-2000), Member of the Stratospheric Observatory for Infrared Astronomy (SOFIA) Science Working Group (1990-1995), Member of the Submillimeter Science Working Group (1985-1995), Member of Executive Council of the American
  • Appendix A: Scientific Notation

    Appendix A: Scientific Notation

    Appendix A: Scientific Notation Since in astronomy we often have to deal with large numbers, writing a lot of zeros is not only cumbersome, but also inefficient and difficult to count. Scientists use the system of scientific notation, where the number of zeros is short handed to a superscript. For example, 10 has one zero and is written as 101 in scientific notation. Similarly, 100 is 102, 100 is 103. So we have: 103 equals a thousand, 106 equals a million, 109 is called a billion (U.S. usage), and 1012 a trillion. Now the U.S. federal government budget is in the trillions of dollars, ordinary people really cannot grasp the magnitude of the number. In the metric system, the prefix kilo- stands for 1,000, e.g., a kilogram. For a million, the prefix mega- is used, e.g. megaton (1,000,000 or 106 ton). A billion hertz (a unit of frequency) is gigahertz, although I have not heard of the use of a giga-meter. More rarely still is the use of tera (1012). For small numbers, the practice is similar. 0.1 is 10À1, 0.01 is 10À2, and 0.001 is 10À3. The prefix of milli- refers to 10À3, e.g. as in millimeter, whereas a micro- second is 10À6 ¼ 0.000001 s. It is now trendy to talk about nano-technology, which refers to solid-state device with sizes on the scale of 10À9 m, or about 10 times the size of an atom. With this kind of shorthand convenience, one can really go overboard.
  • The Development of the First Catalyzed Reaction of Ketenes and Imines: Catalytic, Asymmetric Synthesis of Â-Lactams Andrew E

    The Development of the First Catalyzed Reaction of Ketenes and Imines: Catalytic, Asymmetric Synthesis of Â-Lactams Andrew E

    Published on Web 00/00/0000 The Development of the First Catalyzed Reaction of Ketenes and Imines: Catalytic, Asymmetric Synthesis of â-Lactams Andrew E. Taggi, Ahmed M. Hafez, Harald Wack, Brandon Young, Dana Ferraris, and Thomas Lectka* Contribution from the Department of Chemistry, Johns Hopkins UniVersity, 3400 North Charles Street, Baltimore, Maryland 21218 Received February 5, 2002 Abstract: We report practical methodology for the catalytic, asymmetric synthesis of â-lactams resulting from the development of a catalyzed reaction of ketenes (or their derived zwitterionic enolates) and imines. The products of these asymmetric reactions can serve as precursors to a number of enzyme inhibitors and drug candidates as well as valuable synthetic intermediates. We present a detailed study of the mechanism of the â-lactam forming reaction with proton sponge as the stoichiometric base, including kinetics and isotopic labeling studies. Stereochemical models based on molecular mechanics (MM) calculations are also presented to account for the observed stereoregular sense of induction in our reactions and to provide a guidepost for the design of other catalyst systems. Introduction this structural motif a worthwhile goal for the synthetic organic 10 The clinical relevance of â-lactams continues to expand at a chemist, thus the synthesis of these nonantibiotic â-lactams surprising rate. Although their use as antibiotics is being will be the focus of this contribution. While considerable effort compromised to some extent by bacterial resistance pressures,1 has been put into synthetic methodology to construct the basic recently â-lactams (especially nonnatural ones) have achieved â-lactam skeleton, there have been few general methods many important nonantibiotic uses.
  • Physical Processes in the Interstellar Medium

    Physical Processes in the Interstellar Medium

    Physical Processes in the Interstellar Medium Ralf S. Klessen and Simon C. O. Glover Abstract Interstellar space is filled with a dilute mixture of charged particles, atoms, molecules and dust grains, called the interstellar medium (ISM). Understand- ing its physical properties and dynamical behavior is of pivotal importance to many areas of astronomy and astrophysics. Galaxy formation and evolu- tion, the formation of stars, cosmic nucleosynthesis, the origin of large com- plex, prebiotic molecules and the abundance, structure and growth of dust grains which constitute the fundamental building blocks of planets, all these processes are intimately coupled to the physics of the interstellar medium. However, despite its importance, its structure and evolution is still not fully understood. Observations reveal that the interstellar medium is highly tur- bulent, consists of different chemical phases, and is characterized by complex structure on all resolvable spatial and temporal scales. Our current numerical and theoretical models describe it as a strongly coupled system that is far from equilibrium and where the different components are intricately linked to- gether by complex feedback loops. Describing the interstellar medium is truly a multi-scale and multi-physics problem. In these lecture notes we introduce the microphysics necessary to better understand the interstellar medium. We review the relations between large-scale and small-scale dynamics, we con- sider turbulence as one of the key drivers of galactic evolution, and we review the physical processes that lead to the formation of dense molecular clouds and that govern stellar birth in their interior. Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Straße 2, 69120 Heidelberg, Germany e-mail: [email protected], [email protected] 1 Contents Physical Processes in the Interstellar Medium ...............
  • Laboratory Astrophysics: from Observations to Interpretation

    Laboratory Astrophysics: from Observations to Interpretation

    April 14th – 19th 2019 Jesus College Cambridge UK IAU Symposium 350 Laboratory Astrophysics: From Observations to Interpretation Poster design by: D. Benoit, A. Dawes, E. Sciamma-O’Brien & H. Fraser Scientific Organizing Committee: Local Organizing Committee: Farid Salama (Chair) ★ P. Barklem ★ H. Fraser ★ T. Henning H. Fraser (Chair) ★ D. Benoit ★ R Coster ★ A. Dawes ★ S. Gärtner ★ C. Joblin ★ S. Kwok ★ H. Linnartz ★ L. Mashonkina ★ T. Millar ★ D. Heard ★ S. Ioppolo ★ N. Mason ★ A. Meijer★ P. Rimmer ★ ★ O. Shalabiea★ G. Vidali ★ F. Wa n g ★ G. Del-Zanna E. Sciamma-O’Brien ★ F. Salama ★ C. Wa lsh ★ G. Del-Zanna For more information and to contact us: www.astrochemistry.org.uk/IAU_S350 [email protected] @iaus350labastro 2 Abstract Book Scheduley Sunday 14th April . Pg. 2 Monday 15th April . Pg. 3 Tuesday 16th April . Pg. 4 Wednesday 17th April . Pg. 5 Thursday 18th April . Pg. 6 Friday 19th April . Pg. 7 List of Posters . .Pg. 8 Abstracts of Talks . .Pg. 12 Abstracts of Posters . Pg. 83 yPlenary talks (40') are indicated with `P', review talks (30') with `R', and invited talks (15') with `I'. Schedule Sunday 14th April 14:00 - 17:00 REGISTRATION 18:00 - 19:00 WELCOME RECEPTION 19:30 DINNER BAR OPEN UNTIL 23:00 Back to Table of Contents 2 Monday 15th April 09:00 { 10:00 REGISTRATION 09:00 WELCOME by F. Salama (Chair of SOC) SESSION 1 CHAIR: F. Salama 09:15 E. van Dishoeck (P) Laboratory astrophysics: key to understanding the Universe From Diffuse Clouds to Protostars: Outstanding Questions about the Evolution of 10:00 A.
  • Discoveries of Mass Independent Isotope Effects in the Solar System: Past, Present and Future Mark H

    Discoveries of Mass Independent Isotope Effects in the Solar System: Past, Present and Future Mark H

    Reviews in Mineralogy & Geochemistry Vol. 86 pp. 35–95, 2021 2 Copyright © Mineralogical Society of America Discoveries of Mass Independent Isotope Effects in the Solar System: Past, Present and Future Mark H. Thiemens Department of Chemistry and Biochemistry University of California San Diego La Jolla, California 92093 USA [email protected] Mang Lin State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry, Chinese Academy of Sciences Guangzhou, Guangdong 510640 China University of Chinese Academy of Sciences Beijing 100049 China [email protected] THE BEGINNING OF ISOTOPES Discovery and chemical physics The history of the discovery of stable isotopes and later, their influence of chemical and physical phenomena originates in the 19th century with discovery of radioactivity by Becquerel in 1896 (Becquerel 1896a–g). The discovery catalyzed a range of studies in physics to develop an understanding of the nucleus and the properties influencing its stability and instability that give rise to various decay modes and associated energies. Rutherford and Soddy (1903) later suggested that radioactive change from different types of decay are linked to chemical change. Soddy later found that this is a general phenomenon and radioactive decay of different energies and types are linked to the same element. Soddy (1913) in his paper on intra-atomic charge pinpointed the observations as requiring the observations of the simultaneous character of chemical change from the same position in the periodic chart with radiative emissions required it to be of the same element (same proton number) but differing atomic weight. This is only energetically accommodated by a change in neutrons and it was this paper that the name “isotope” emerges.