DOCSLIB.ORG

Product Detection of the CH Radical Reactions with Ammonia and Methyl-Substituted Amines Jérémy Bourgalais, Kacee L

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
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 15 16 France 17 18 2Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, USA 19 20 3Astrophysique de Laboratoire, Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - 21 UMR 6251, F-35000 Rennes, France 22 23 24 4 25 Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, 26 27 California 94551, USA 28 29 *Corresponding Author: [email protected] 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 1 ACS Paragon Plus Environment The Journal of Physical Chemistry Page 2 of 47 1 2 3 4 5 6 ABSTRACT 7 8 Reactions of the methylidyne (CH) radical with ammonia (NH3), methylamine (CH3NH2), 9 10 dimethylamine ((CH3)2NH), and trimethylamine ((CH3)3N), have been investigated under 11 12 multiple collision conditions at 373 K and 4 Torr. The reaction products are detected using soft 13 14 15 photoionization coupled to orthogonal acceleration time-of-flight mass spectrometry at the 16 17 Advanced Light Source (ALS) synchrotron. Kinetic traces are employed to discriminate 18 19 between CH reaction products and products from secondary or slower reactions. Branching 20 21 22 ratios for isomers produced at a given mass and formed by a single reaction are obtained by 23 24 fitting the observed photoionization spectra to linear combinations of pure compound spectra. 25 26 The reaction of the CH radical with ammonia is found to form mainly imine, HN=CH2, in line 27 28 29 with an addition–elimination mechanism. The singly methyl substituted imine is detected for 30 31 the CH reactions with methylamine, dimethylamine, and trimethylamine. Dimethylimine 32 33 isomers are formed by the reaction of CH with dimethylamine, while trimethylimine is formed 34 35 by the CH reaction with trimethylamine. Overall, the temporal profiles of the products are not 36 37 38 consistent with the formation of amino carbene products in the reaction flow tube. In the case 39 40 of the reactions with methylamine and dimethylamine, product formation is assigned to an 41 42 addition-elimination mechanism similar to that proposed for the CH reaction with ammonia. 43 44 45 However, this mechanism cannot explain the products detected by the reaction with 46 47 trimethylamine. A C–H insertion pathway may become more probable as the number of methyl 48 49 group increases. 50 51 52 53 54 55 56 57 58 59 60 2 ACS Paragon Plus Environment Page 3 of 47 The Journal of Physical Chemistry 1 2 3 1. INTRODUCTION 4 5 6 Ammonia and its amine derivatives are emitted as gases in the atmosphere from a variety of 7 8 sources such as biomass burning, vegetation, combustion, as well as industry.1,2 These 9 10 nitrogen-containing molecules are of special interest in combustion environments where they 11 12 impact the oxidation and ignition of hydrocarbon fuels.3,4 In addition, their chemistry in 13 14 5-10 15 reactive carbon-rich environments may play a significant role in the formation of NOx. An 16 17 improved utilization of biomass-derived nitrogen-containing compounds as fuels and a better 18 19 understanding of the role of amines in combustion both require a systematic study of the 20 21 22 chemistry of ammonia and substituted amines with combustion relevant radicals. 23 24 A large number of experiments have been performed to investigate the reaction of 25 26 11-15 ammonia with radicals such as OH, CN, C2H, and CH. Although its reaction with the OH 27 28 -13 3 -1 11 29 radical is found to be slow (<510 cm s from 230 K to 450 K), ammonia reacts at a 30 12 13 14 31 significant fraction of the collision rate with the CN, C2H, and CH radicals. In the case of 32 33 the reactions with OH and CN, the products are predicted to mostly be NH + H O and NH + 34 2 2 2 35 13,16,17 36 HCN. The reaction with OH proceeds directly through a HO–HNH2 abstraction saddle 37 16 38 point, while the reaction with CN initially forms a NC–NH3 adduct that may rearrange and 39 40 dissociate to form the final products.13,17 The most exhaustive experimental and theoretical 41 42 15 43 studies have been performed for the CH + NH3 reaction. The mechanism has been assigned 44 45 as addition–elimination, as further described in this introduction. Kinetic investigations with 46 47 methyl-substituted amines are scarcer and data are available only for reactions with OH and 48 49 CH radicals.14,18-22 Reactions with the OH radical proceed with a rate coefficient on the order 50 51 52 of 110-11 cm3 s-1 and are predicted to occur through interaction of the OH radical with an H- 53 54 atom of both the amine and methyl groups to give the abstraction products.18 Reactions of the 55 56 -10 3 -1 14 57 CH radical with methyl substituted amines are fast (>110 cm s ) although no mechanistic 58 59 information is available. 60 3 ACS Paragon Plus Environment The Journal of Physical Chemistry Page 4 of 47 1 2 3 The methylidyne (CH) radical is an important reactive intermediate detected in 4 5 13,16,23,24 6 hydrocarbon flames (e.g., methane, acetylene, ethene, ethane, propene, propane). Its 7 8 barrier-less addition toward a large number of organic and inorganic functional groups is due 9 10 to the carbon atom having both one singly occupied and one empty non-bonding molecular 11 12 orbital. Its formation in flames, along with other fuel-derived C -radicals (e.g., CH , CH and 13 1 3 2 14 15 C), occurs primarily from oxidation of small hydrocarbon compounds (e.g., methane, 16 17 acetylene).17,25 Once formed, the CH radical is likely to play a role in the formation of soot 18 19 precursors through generation of small cyclic hydrocarbons.23-28 A major interest of the CH 20 21 22 radical in combustion is its ability to react with molecular nitrogen to form NCN, which is the 23 24 dominant source of prompt NO formation in turbulent diffusion flames.17,25-38 Its reaction with 25 26 ammonia is also included in a recent combustion model.25 As fuel complexity is increased, 27 28 29 there is a need for additional data about the reaction of the CH radical with nitrogen containing 30 31 hydrocarbons. 32 33 Zabarnick et al.14 performed the first kinetic measurements of CH radical reactions with 34 35 ammonia and methyl substituted amines. They employed pulsed laser photolysis (PLP) and 36 37 38 laser-induced fluorescence (LIF) to measure rate constants for CH with NH3, CH3NH2, 39 40 (CH3)2NH and (CH3)3N at temperatures ranging from room temperature up to 677 K. Based on 41 42 the observed large rate coefficients they suggested an insertion–elimination mechanism of CH 43 44 45 into one of the N-H bonds followed by rapid dissociation of the energized complex. Bocherel 46 39 47 et al. measured the CH + NH3 reaction also using a PLP–LIF technique in a supersonic flow 48 49 reactor between 23 and 295 K. The reaction rate coefficient is 1.3710-10 cm3 s-1 at 295 K and 50 51 52 displays no significant temperature (2.2110-10 cm3 s-1 at 23 K) or pressure dependences in 53 54 agreement with the study of Zabarnick et al.14 More recently Blitz et al.15 investigated the 55 56 products of the CH + NH reaction by measuring the H-atom branching ratio using LIF. The 57 3 58 59 close to unity H-atom branching ratio combined with high-level (MCSCF/CASSCF) 60 4 ACS Paragon Plus Environment Page 5 of 47 The Journal of Physical Chemistry 1 2 3 calculations15 support an insertion–elimination mechanism similar to that proposed for the 4 5 40 6 reactions of CH with saturated hydrocarbons.
Load more

Recommended publications
  • 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.
    [Show full text]
  • 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 ).
    [Show full text]
  • Aromatic Formation Promoted by Ion-Driven Radical Pathways In
    Aromatic Formation Promoted by Ion-Driven Radical Pathways in EUV Photochemical Experiments Simulating Titan’s Atmospheric Chemistry Jérémy Bourgalais, Nathalie Carrasco, Ludovic Vettier, Antoine Comby, Dominique Descamps, Stephane Petit, Valérie Blanchet, Jerôme Gaudin, Yann Mairesse, Bernard Marty To cite this version: Jérémy Bourgalais, Nathalie Carrasco, Ludovic Vettier, Antoine Comby, Dominique Descamps, et al.. Aromatic Formation Promoted by Ion-Driven Radical Pathways in EUV Photochemical Experiments Simulating Titan’s Atmospheric Chemistry. Journal of Physical Chemistry A, American Chemical Society, 2021, 125 (15), pp.3159-3168. 10.1021/acs.jpca.1c00324. insu-03201041 HAL Id: insu-03201041 https://hal-insu.archives-ouvertes.fr/insu-03201041 Submitted on 18 May 2021 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. Aromatic Formation Promoted by Ion-Driven Radical Pathways in EUV Photochemical Experiments Simulating Titan's Atmospheric Chemistry J´er´emyBourgalais,∗,y,z,k Nathalie Carrasco,y Ludovic Vettier,y Antoine Comby,{ Dominique Descamps,{
    [Show full text]
  • A Chemical Dynamics Study on the Gas-Phase Formation of Triplet and Singlet C5H2 Carbenes Chao Hea,1, Galiya R
    A chemical dynamics study on the gas-phase formation of triplet and singlet C5H2 carbenes Chao Hea,1, Galiya R. Galimovab,c,1, Yuheng Luoa,1, Long Zhaoa, André K. Eckhardtd, Rui Suna,2, Alexander M. Mebelb,2, and Ralf I. Kaisera,2 aDepartment of Chemistry, University of Hawai’i at Manoa, Honolulu, HI 96822; bDepartment of Chemistry and Biochemistry, Florida International University, Miami, FL 33199; cLaboratory of Combustion Physics and Chemistry, Samara National Research University, Samara 443086, Russia; and dInstitute of Organic Chemistry, Justus Liebig University, 35392 Giessen, Germany Edited by Alexis T. Bell, University of California, Berkeley, CA, and approved October 14, 2020 (received for review September 15, 2020) Since the postulation of carbenes by Buchner (1903) and Staudinger helium–acetylene discharge (13) prior to its observation toward (1912) as electron-deficient transient species carrying a divalent car- TMC-1 (4). Cyclopropenylidene (1) ring opens to propargylene (3) bon atom, carbenes have emerged as key reactive intermediates in upon photoexcitation at 360 nm (3, 5). The triplet multiplicity of the organic synthesis and in molecular mass growth processes leading electronic ground state of the C2 symmetric propargylene (3), in eventually to carbonaceous nanostructures in the interstellar medium which each unpaired electron is formally located at each terminal and in combustion systems. Contemplating the short lifetimes of carbon atom, leading to an unconventional 1,3-diradical, was rec- these transient molecules and their tendency for dimerization, free ognized by Mebel et al., who computed the ground triplet 3B to lie − carbenes represent one of the foremost obscured classes of organic 53 to 61 kJ·mol 1 below the first excited singlet 1A′ state (14–16).
    [Show full text]
  • United States Patent (15) 3,678,014 Suzuki Et Al
    United States Patent (15) 3,678,014 Suzuki et al. (45) July 18, 1972 54 LOW TEMPERATURE PEROXDE OTHER PUBLICATIONS CURABLE THERMOSETTING The Chemistry of Organic Film Formers, Solomon John Wiley POLYURETHANE RESN HAVING and Sons, N.Y. 1967 pp. 50-54. TERMINAL UNSATURATION Primary Examiner-Donald E. Czaja 72 Inventors: Hisao Suzuki, Fujisawa-shi; Akira Assistant Examiner-Eugene C. Rzucidlo Musashi, Kanagawa-ken; Makoto Hiruta, Attorney-George B. Oujevolk Kanagawa-ken; Hiroo Muramoto, Kanagawa-ken, all of Japan 57) ABSTRACT 73) Assignee: Nippon Soda Co., Ltd., Tokyo, Japan A thermosetting resin having the formula: (22 Filed: Aug. 7, 1969 (21) Appl. No.: 849,298 YCH=CX-Alt-Jn-Girls-D-E (PBd -E-D Gn - LN n 52 U.S. C. ...........260/77.5CR, 260/77.5 CH, 260/94.7N, 260/859 Jn-A1-CX-CHY I51) Int. Cl.......................................................... C08g 22/00 58) Field of Search.............. 260/77.5 CR, 77.5 CH, 94.7N, wherein X is hydrogen, or an alkyl radical containing up to 260/859 R four carbon atoms; Y is selected from the group consisting of hydrogen, phenyl, and alkoxycarbonyl; A is a carboxyl, or a carbonyl group; J is an alkylene group containing less than five carbon atoms and G is selected from the group consisting of (56) References Cited urethane, carboimino and ureylene group; E is urethane or carboimino, and can be the same or different from G; D is UNITED STATES PATENTS selected from the group consisting of alkylene, cycloalkylene, 2,808,391 10/1957 Pattison................................. 260/453 phenylene, naphthylene, pyrene, bis(phenylene)-methylene 2,877,212 3/1959 Seligman.............................
    [Show full text]
  • On the Formation of Nitrogen-Substituted Polycyclic Aromatic Hydrocarbons (Npahs) in Cite This: Chem
    Chem Soc Rev REVIEW ARTICLE On the formation of nitrogen-substituted polycyclic aromatic hydrocarbons (NPAHs) in Cite this: Chem. Soc. Rev., 2017, 46,452 circumstellar and interstellar environments Dorian S. N. Parker† and Ralf I. Kaiser* The chemical evolution of extraterrestrial environments leads to the formation of polycyclic aromatic hydrocarbons (PAHs) via gas phase radical mediated aromatization reactions. We review that these de facto barrierless reactions are capable of forming prebiotic molecules such as nitrogen substituted PAHs (NPAHs), which represent the missing link between nitrogen bearing acyclic molecules and prebiotic nucleobases along with vitamins found in meteorites. Crucial routes leading to the incorporation of nitrogen atoms into the aromatic ring have been exposed. Pyridine can be formed from the reaction of abundant vinyl cyanide and its radical or via cyano radicals reacting with 1,3-butadiene. The NPAHs Received 3rd October 2016 1,4-dihydro(iso)quinoline and (iso)quinoline can be synthesized through reaction of pyridyl radicals with DOI: 10.1039/c6cs00714g 1,3-butadiene or sequentially with two acetylene molecules, respectively. The inclusion of nitrogen into an aromatic system and their growth can fill the mechanistic gaps missing leading from acyclic nitrogen- www.rsc.org/chemsocrev bearing molecules via pyridine to NPAH-type molecules in the interstellar medium. 1. Introduction Department of Chemistry, University of Hawai’i at Manoa, Honolulu, HI 96822, During the last decade, considerable progress has been made USA. E-mail: [email protected] † Present address: M Squared Lasers Ltd, 1 Kelvin Campus, Maryhill Road, in untangling the elementary reactions leading to the gas phase Glasgow, UK, G20 0SP.
    [Show full text]
  • Mechanisms for Ethanol Electrooxidation on Pt(111) and Adsorption Bond Strengths Defining an Ideal Catalyst Haleema Aied Asiri and Alfred B
    Journal of The Electrochemical Society, 162 (1) F115-F122 (2015) F115 Mechanisms for Ethanol Electrooxidation on Pt(111) and Adsorption Bond Strengths Defining an Ideal Catalyst Haleema Aied Asiri and Alfred B. Anderson∗,z Chemistry Department, Case Western Reserve University, Cleveland, Ohio 44106-7078, USA Ethanol electrooxidation on the Pt(111) electrode has been studied with computational theory. Using a solvation model and a modified Poison-Boltzmann theory for electrolyte polarization, standard reversible potentials for forming 17 reaction intermediates in solution were calculated with density functional theory. Reversible potentials for adsorbed intermediates were then determined by inputting calculated adsorption energies into a linear Gibbs energy relationship. A path to CO2 was found where surface potentials were low and close to the calculated 0.004 V reversible potential for the 12 electron oxidation of ethanol. An exception was the 0.49 V potential for forming the OH(ads) from H2O(l), this being required for oxidation of CO(ads) and RH(ads) intermediates. The surface potentials show that acetyl, OCCH3(ads) forms at small positive potentials and decomposes to CH(ads), CH3(ads), and CO(ads), which poison the surface at these potentials. Energy losses due to non-electron transfer reaction steps are small and cause a small shift in the reversible potential for the 12 electron oxidation. Values for adsorption bond strengths over a perfect catalyst were determined. It is concluded that on an ideal catalyst most intermediates will adsorb more weakly and OH more strongly than on Pt(111). © The Author(s) 2014. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.
    [Show full text]
  • The Neutral Photochemistry of Nitriles, Amines and Imines in the Atmosphere of Titan
    The neutral photochemistry of nitriles, amines and imines in the atmosphere of Titan J.C. Loisonc,d, E. H´ebrarda,b, M. Dobrijevica,b,∗, K.M. Hicksonc,d, F. Caralpc,d, V. Huea,b, G. Gronoffe, O. Venotf, Y. Benilang aUniversit´ede Bordeaux, Laboratoire d'Astrophysique de Bordeaux, UMR 5804, F-33270 Floirac, France bCNRS, Laboratoire d'Astrophysique de Bordeaux, UMR 5804, F-33270, Floirac, France cUniversit´ede Bordeaux, Institut des Sciences Mol´eculaires, UMR 5255, F-33400 Talence, France dCNRS, Institut des Sciences Mol´eculaires, UMR 5255, F-33400 Talence, France eSSAI/NASA LaRC, Hampton, Va, USA fKatholieke Univ Leuven, Inst Sterrenkunde, B-3001 Louvain, Belgium gLaboratoire Interuniversitaire des Syst`emesAtmosph´eriques, UMR CNRS 7583, Universit´esParis Est Cr´eteil(UPEC) et Paris Diderot (UPD), Cr´eteil,France Abstract The photochemistry of N2 and CH4 in the atmosphere of Titan leads to a very rich chemistry which is not well understood. The aim of our study is to improve our understanding of the production of nitrogen compounds and to predict the abundances of those with high molar mass with better accuracy. We have made a careful investigation of the neutral nitrogen photochemistry to improve current chemical schemes including the most abundant species and the most efficient reactions. We also studied the propagation of uncertainties on rate constants in our model and determined the key reactions from a global sensitivity analysis. Our photochemical model contains 124 species, 60 of which are nitrogen con- taining compounds, and 1141 reactions. Our results are in reasonable agreement with Cassini/INMS data in the higher atmosphere but our model overestimates the mole fractions of several nitriles in the lower stratosphere.
    [Show full text]
  • Arxiv:1510.07052V1 [Astro-Ph.EP] 23 Oct 2015 99 Lae Ta.20,Adrfrne Therein)
    A Chemical Kinetics Network for Lightning and Life in Planetary Atmospheres P. B. Rimmer1 and Ch Helling School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, United Kingdom ABSTRACT There are many open questions about prebiotic chemistry in both planetary and exoplane- tary environments. The increasing number of known exoplanets and other ultra-cool, substellar objects has propelled the desire to detect life and prebiotic 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 K and 30000 K. Formation pathways for glycine and other organic molecules are included. The network is complete up to H6C2N2O3. Stand2015 is successfully tested against atmo- spheric chemistry models for HD209458b, Jupiter and the present-day Earth using a simple 1D photochemistry/diffusion code. Our results for the early Earth agree with those of Kasting (1993) 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. Very little glycine is produced in the absence of any molecular nitrogen and oxygen. This suggests that production of glycine is inhibited if a gas is too strongly reducing. Possible applications and limitations of the chemical kinetics network are also discussed. Subject headings: astrobiology — atmospheric effects — molecular processes — planetary systems 1. Introduction The input energy source and the initial chem- istry have been varied across these different ex- The potential connection between a focused periments.
    [Show full text]
  • CH Abundance Gradient in TMC-1⋆
    A&A 531, A121 (2011) Astronomy DOI: 10.1051/0004-6361/201016079 & c ESO 2011 Astrophysics CH abundance gradient in TMC-1 A. Suutarinen1,W.D.Geppert2, J. Harju1,3, A. Heikkilä4, S. Hotzel3,5,M.Juvela1,3, T. J. Millar6, C. Walsh6, and J. G. A. Wouterloot7 1 Department of Physics, PO Box 64, 00014 University of Helsinki, Finland e-mail: [email protected] 2 Department of Physics, AlbaNova, 10691 Stockholm, Sweden 3 Observatory, University of Helsinki, Finland 4 Onsala Space Observatory, 43992 Onsala, Sweden 5 GRS mbH, 50667 Cologne, Germany 6 Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, University Road, Belfast, BT7 1NN, UK 7 Joint Astronomy Centre, Hilo, 96720, USA Received 5 November 2010 / Accepted 14 May 2011 ABSTRACT Aims. The aim of this study is to examine if the well-known chemical gradient in TMC-1 is reflected in the amount of rudimentary forms of carbon available in the gas-phase. As a tracer we use the CH radical which is supposed to be well correlated with carbon atoms and simple hydrocarbon ions. Methods. We observed the 9-cm Λ-doubling lines of CH along the dense filament of TMC-1. The CH column densities were compared with the total H2 column densities derived using the 2MASS NIR data and previously published SCUBA maps and with OH column densities derived using previous observations with Effelsberg. We also modelled the chemical evolution of TMC-1 adopting physical conditions typical of dark clouds using the UMIST Database for Astrochemistry gas-phase reaction network to aid the interpretation of the observed OH/CH abundance ratios.
    [Show full text]
  • {Download PDF}
    NO! PDF, EPUB, EBOOK Marta Altes | 32 pages | 15 May 2012 | Child's Play International Ltd | 9781846434174 | English | Swindon, United Kingdom trình giả lập trên PC và Mac miễn phí – Tải NoxPlayer Don't have an account? Sign up here. Already have an account? Log in here. By creating an account, you agree to the Privacy Policy and the Terms and Policies , and to receive email from Rotten Tomatoes and Fandango. Please enter your email address and we will email you a new password. We want to hear what you have to say but need to verify your account. Just leave us a message here and we will work on getting you verified. No uses its history-driven storyline to offer a bit of smart, darkly funny perspective on modern democracy and human nature. Rate this movie. Oof, that was Rotten. Meh, it passed the time. So Fresh: Absolute Must See! You're almost there! Just confirm how you got your ticket. Cinemark Coming Soon. Regal Coming Soon. By opting to have your ticket verified for this movie, you are allowing us to check the email address associated with your Rotten Tomatoes account against an email address associated with a Fandango ticket purchase for the same movie. Geoffrey Macnab. Gripping and suspenseful even though the ending is already known. Rene Rodriguez. The best movie ever made about Chilean plebiscites, No thoroughly deserves its Oscar nomination for Best Foreign Film. Anthony Lane. Soren Andersen. Calvin Wilson. A cunning and richly enjoyable combination of high-stakes drama and media satire from Chilean director Pablo Larrain.
    [Show full text]
  • PAH Growth in Flames and Space: Formation of Phenalenyl Radical
    PAH growth in flames and space: Formation of phenalenyl radical Zachariah D. Levey,y Benjamin A. Laws,y Srivathsan P. Sundar,z Klaas Nauta,y Scott H. Kable,y Gabriel da Silva,z John F. Stanton,{ and Timothy W. Schmidt∗,x ySchool of Chemistry, University of New South Wales, Sydney NSW 2052, Australia zDepartment of Chemical Engineering, The University of Melbourne, Parkville 3010, Australia {Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA xCentre of Excellence in Exciton Science, University of New South Wales, Sydney NSW 2052, Australia E-mail: [email protected] Abstract Polycyclic aromatic hydrocarbons (PAHs) are intermediates in the formation of soot parti- cles and interstellar grains. However, their formation mechanisms in combustion and interstel- lar environments are not fully understood. The production of tricyclic PAHs and, in particular, the conversion of a PAH containing a five-membered ring to one with a six-membered ring is of interest to explain PAH abundances in combustion processes. In the present work, reso- nant ionization mass spectrometry in conjunction with isotopic labelling is used to investigate the formation of the phenalenyl radical from acenaphthylene and methane in an electrical dis- charge. We show that in this environment, the CH cycloaddition mechanism converts a five- membered ring to a six-membered ring. This mechanism can occur in tandem with other PAH 1 formation mechanisms such as hydrogen abstraction/ acetylene addition (HACA) to produce larger PAHs in flames and the interstellar medium. Introduction Polycyclic aromatic hydrocarbons (PAHs) are early intermediates in the soot formation process in both terrestrial1–3 and interstellar environments4–7.
    [Show full text]