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Woon DE. Icy Grain Mantle Surface Astrochemistry of MgNC: The Emergence of Metal Ion Catalysis Studied via Model Ice Cluster Calculations. J Phys Chem A 2022; 126:5186-5194. [PMID: 35895034 DOI: 10.1021/acs.jpca.2c01739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One of a small number of known magnesium-containing astromolecules, magnesium isocyanide (MgNC) was first detected in 1986. MgNC is an intriguing reactant to consider: it is an open-shell radical in which its metal atom forms a bond with CN that is a mixture of ionic and covalent character. While its gas phase astrochemistry has received prior attention, the grain surface chemistry of MgNC has never been studied. Because of its ionic character, MgNC is found to interact far more strongly with an ice surface than molecules with a greater degree of covalency. As a radical, it may react with closed-shell molecules deposited from the gas phase. In this work, cluster calculations treated with density functional theory and correlation consistent basis sets were used to model the deposition of MgNC on clusters containing 17 and 24 water molecules, which were then allowed to react with acetylene (HCCH) and hydrogen cyanide (HCN) as well as with H atoms. The addition of H to MgNC-nH2O yields hydromagnesium isocyanide (HMgNC), a known astromolecule that may be ejected into the gas phase. HCCH and HCN bind to MgNC-nH2O to form intermediate radical compounds that may then also react with H atoms. There is enough reaction energy from H addition to eject fragments of the intermediates into the gas phase: the vinyl radical (C2H3) for HCCH and the methaniminyl radical (H2CN) for HCN. That leaves MgNC-nH2O to perform further catalytic activity. Alternatively, various hydrogenated divalent Mg compounds may also be stabilized and frozen into the ice or potentially ejected into the gas phase. Benchmark coupled cluster theory calculations in limited systems were used to characterize the submerged reaction barriers present when HCCH or HCN add to MgNC in the gas phase.
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Affiliation(s)
- David E Woon
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
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Woon DE. Quantum Chemical Cluster Studies of Cation-Ice Reactions for Astrochemical Applications: Seeking Experimental Confirmation. Acc Chem Res 2021; 54:490-497. [PMID: 33444014 DOI: 10.1021/acs.accounts.0c00717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
ConspectusInterstellar clouds and the outer reaches of protostellar and protoplanetary systems are very cold environments where chemistry is limited to processes that have little or no reaction barrier (in the absence of external energy input). This account reviews what is known about cation-ice reactions, which are not currently incorporated in astrochemical network models. Quantum chemical cluster calculations using density functional theory have shown that barrierless reactions can occur when gas phase cations such as HCO+, OH+, CH3+, and C+ are deposited on an icy grain mantle with energies commensurate with other gas phase species. When cations react with molecules on ice surfaces, the pathways and products often differ significantly from gas phase chemistry due to the involvement of water and other molecules in the ice. The reactions studied to date have found pathways to abundant and important astromolecules such as methanol, formic acid, and carbon dioxide that are very favorable and may be more efficient pathways than gas phase processes. Other products that can be produced include glycolonitrile, its precursors, and related isocyanide compounds. This account describes for the first time ice surface reactions between the carbon cation, C+, and two common astromolecules, methanol (CH3OH) and formic acid (HCOOH), which can yield precursors to glyoxal, hydroxyketene, vinyl alcohol, and acetaldehyde. The quantum chemical methodology used to explore reaction surfaces is also used to predict both vibrational and electronic spectra of reactant and product ices, which offers guidance for possible experimental studies of these reactions. While theoretical calculations indicate that cation-ice reactions are efficient and offer novel pathways to important astrochemical compounds, experimental confirmation would be very welcome. Cations and ice-covered grain mantles are certainly present in cold astrophysical environments. The account concludes with a discussion of how cation-ice reactions could be incorporated into reaction network models of the formation and destruction of molecules in interstellar clouds and protoplanetary systems. Further studies will involve characterizing additional rcactions and more extensive treatment of the most important cation-ice reactions to better ascertain reaction branching outcomes.
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Affiliation(s)
- David E. Woon
- Department of Chemistry, University of Illinois at Urbana−Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
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van Dishoeck EF. Astrochemistry of dust, ice and gas: introduction and overview. Faraday Discuss 2014; 168:9-47. [DOI: 10.1039/c4fd00140k] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A brief introduction and overview of the astrochemistry of dust, ice and gas and their interplay is presented. The importance of basic chemical physics studies of critical reactions is illustrated through a number of recent examples. Such studies have also triggered new insight into chemistry, illustrating how astronomy and chemistry can enhance each other. Much of the chemistry in star- and planet-forming regions is now thought to be driven by gas–grain chemistry rather than pure gas-phase chemistry, and a critical discussion of the state of such models is given. Recent developments in studies of diffuse clouds and PDRs, cold dense clouds, hot cores, protoplanetary disks and exoplanetary atmospheres are summarized, both for simple and more complex molecules, with links to papers presented in this volume. In spite of many lingering uncertainties, the future of astrochemistry is bright: new observational facilities promise major advances in our understanding of the journey of gas, ice and dust from clouds to planets.
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Affiliation(s)
- Ewine F. van Dishoeck
- Leiden Observatory
- Leiden University
- 2300 RA Leiden, the Netherlands
- Max-Planck-Institute für Extraterrestrische Physik
- Garching, Germany
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Thomas PS, Somers MF, Hoekstra AW, Kroes GJ. Chebyshev high-dimensional model representation (Chebyshev-HDMR) potentials: application to reactive scattering of H2 from Pt(111) and Cu(111) surfaces. Phys Chem Chem Phys 2012; 14:8628-43. [DOI: 10.1039/c2cp40173h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Didriche K, Herman M. A four-atom molecule at the forefront of spectroscopy, intramolecular dynamics and astrochemistry: Acetylene. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.07.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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McCarroll R. Influence of internal rotation on exothermic reactions between neutral molecules at low temperatures. J Phys Chem A 2009; 113:14845-50. [PMID: 19791788 DOI: 10.1021/jp905000y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A Langevin-type transition state model is developed to take account of the internal rotation energy in exothermic reactive collisions between neutral molecules. Energy and total angular momentum are both rigorously conserved. Reactive rate coefficients attain a maximum of a few 10(-10) cm(3)/s at temperatures in the range 10-30 K decreasing rapidly at higher temperatures. Results for a representative selection of well-studied systems, Si-O(2), CN-O(2), Si-NO, are in good agreement with experimental observations. At higher temperatures, typically around 100 K or greater, the rate coefficient exhibits a T(-1/3) dependence.
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Affiliation(s)
- Ronald McCarroll
- Laboratoire de Chimie Physique-Matière et Rayonnement, UMR 7614 du CNRS, Université Pierre et Marie Curie, 75231-Paris Cedex 05, France.
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Woon DE. Quantum Chemical Evaluation of the Astrochemical Significance of Reactions between S Atom and Acetylene or Ethylene. J Phys Chem A 2007; 111:11249-53. [PMID: 17536790 DOI: 10.1021/jp0708392] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Addition-elimination reactions of S atom in its 3P ground state with acetylene (C2H2) and ethylene (C2H4) were characterized with both molecular orbital and density functional theory calculations employing correlation consistent basis sets in order to assess the likelihood that either reaction might play a general role in astrochemistry or a specific role in the formation of S2 (X3Sigmag-) via a mechanism proposed by Saxena, P. P.; Misra, A. Mon. Not. R. Astron. Soc. 1995, 272, 89. The acetylene and ethylene reactions proceed through C2H2S (3A' ') and C2H4S (3A' ') intermediates, respectively, to yield HCCS (2Pi) and C2H3S (2A'). Substantial barriers were found in the exit channels for every combination of method and basis set considered in this work, which effectively precludes hydrogen elimination pathways for both S + C2H2 and S + C2H4 in the ultracold interstellar medium where only very modest barriers can be surmounted and processes without barriers tend to predominate. However, if one or both intermediates are formed and stabilized efficiently under cometary or dense interstellar cloud conditions, they could serve as temporary reservoirs for the S atom and participate in reactions such as S + C2H2S --> S2 + C2H2 or S + C2H4S --> S2 + C2H4. For formation and stabilization to be efficient, the reaction must possess a barrier height small enough to be surmountable at low temperatures yet large enough to prevent redissociation to reactants. Barrier heights computed with B3LYP and large basis sets are very low, but more rigorous QCISD(T) and RCCSD(T) results indicate that the barrier heights are closer to 3-4 kcal/mol. The calculations therefore indicate that S + C2H2 or S + C2H4 could contribute to the formation of S2 in comets and may serve as a means to gauge coma temperature. The energetics of the ethylene reaction are more favorable.
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Affiliation(s)
- David E Woon
- Molecular Research Institute, 1000 Elwell Court, Suite 105, Palo Alto, California 94303, USA.
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Modeling chemical growth processes in Titan’s atmosphere: 1. Theoretical rates for reactions between benzene and the ethynyl (C2H) and cyano (CN) radicals at low temperature and pressure. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2006.09.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Yu HT, Zhao YL, Kan W, Fu HG. A theoretical study on the radical–neutral reaction mechanism of carbon monophosphide, CP, with acetylene, C2H2. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.theochem.2006.06.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Flores JR, Estévez CM, Carballeira L, Juste IP. A Theoretical Study of the S + C2H Reaction: Potential Energy Surfaces and Dynamics. J Phys Chem A 2001. [DOI: 10.1021/jp004169a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. R. Flores
- Departamento de Química Física, Facultad de Ciencias, Campus de Vigo, Universidad de Vigo, 36200-Vigo, Spain
| | - C. M. Estévez
- Departamento de Química Física, Facultad de Ciencias, Campus de Vigo, Universidad de Vigo, 36200-Vigo, Spain
| | - L. Carballeira
- Departamento de Química Física, Facultad de Ciencias, Campus de Vigo, Universidad de Vigo, 36200-Vigo, Spain
| | - I. Pérez Juste
- Departamento de Química Física, Facultad de Ciencias, Campus de Vigo, Universidad de Vigo, 36200-Vigo, Spain
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Basiuk VA. Formation of Amino Acid Precursors in the Interstellar Medium. A DFT Study of Some Gas-Phase Reactions Starting with Methylenimine. J Phys Chem A 2001. [DOI: 10.1021/jp004116t] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vladimir A. Basiuk
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior C.U.; A. Postal 70−543, 04510 México D.F., Mexico
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Huang LCL, Asvany O, Chang AHH, Balucani N, Lin SH, Lee YT, Kaiser RI, Osamura Y. Crossed beam reaction of cyano radicals with hydrocarbon molecules. IV. Chemical dynamics of cyanoacetylene (HCCCN; X 1Σ+) formation from reaction of CN(X 2Σ+) with acetylene, C2H2(X 1Σg+). J Chem Phys 2000. [DOI: 10.1063/1.1289530] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Barrientos C, Redondo P, Largo A. Reaction of C3H2+ with Atomic Nitrogen: A Theoretical Study. J Phys Chem A 2000. [DOI: 10.1021/jp002454o] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Carmen Barrientos
- Departamento de Química Física, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid, Spain
| | - Pilar Redondo
- Departamento de Química Física, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid, Spain
| | - Antonio Largo
- Departamento de Química Física, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid, Spain
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Lee S, Samuels DA, Hoobler RJ, Leone SR. Direct measurements of rate coefficients for the reaction of ethynyl radical (C2H) with C2H2at 90 and 120 K using a pulsed Laval nozzle apparatus. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999je001187] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Faure A, Wiesenfeld L, Valiron P. Temperature dependence of fast neutral–neutral reactions: a triatomic model study. Chem Phys 2000. [DOI: 10.1016/s0301-0104(99)00369-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Ion-molecule chemistry in interstellar clouds. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s1071-9687(98)80003-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Herbst E, Woon DE. The rate of the reaction between C2H and C2H2 at interstellar temperatures. THE ASTROPHYSICAL JOURNAL 1997; 489:109-112. [PMID: 11541459 DOI: 10.1086/304786] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The reaction between the radical C2H and the stable hydrocarbon C2H2 is one of the simplest neutral-neutral hydrocarbon reactions in chemical models of dense interstellar clouds and carbon-rich circumstellar shells. Although known to be rapid at temperatures > or = 300 K, the reaction has yet to be studied at lower temperatures. We present here ab initio calculations of the potential surface for this reaction and dynamical calculations to determine its rate at low temperature. Despite a small potential barrier in the exit channel, the calculated rate is large, showing that this reaction and, most probably, more complex analogs contribute to the formation of complex organic molecules in low-temperature sources.
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Affiliation(s)
- E Herbst
- Department of Physics, Ohio State University, Columbus 43210-1106, USA.
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