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Nixon CA. The Composition and Chemistry of Titan's Atmosphere. ACS EARTH & SPACE CHEMISTRY 2024; 8:406-456. [PMID: 38533193 PMCID: PMC10961852 DOI: 10.1021/acsearthspacechem.2c00041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 11/02/2023] [Accepted: 02/02/2024] [Indexed: 03/28/2024]
Abstract
In this review I summarize the current state of knowledge about the composition of Titan's atmosphere and our current understanding of the suggested chemistry that leads to that observed composition. I begin with our present knowledge of the atmospheric composition, garnered from a variety of measurements including Cassini-Huygens, the Atacama Large Millimeter/submillimeter Array, and other ground- and space-based telescopes. This review focuses on the typical vertical profiles of gases at low latitudes rather than global and temporal variations. The main body of the review presents a chemical description of how complex molecules are believed to arise from simpler species, considering all known "stable" molecules-those that have been uniquely identified in the neutral atmosphere. The last section of the review is devoted to the gaps in our present knowledge of Titan's chemical composition and how further work may fill those gaps.
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Affiliation(s)
- Conor A. Nixon
- Planetary Systems Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, United
States
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Chang Y, Yang J, Chen Z, Zhang Z, Yu Y, Li Q, He Z, Zhang W, Wu G, Ingle RA, Bain M, Ashfold MNR, Yuan K, Yang X, Hansen CS. Ultraviolet photochemistry of ethane: implications for the atmospheric chemistry of the gas giants. Chem Sci 2020; 11:5089-5097. [PMID: 34122966 PMCID: PMC8159213 DOI: 10.1039/d0sc01746a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 04/29/2020] [Indexed: 11/23/2022] Open
Abstract
Chemical processing in the stratospheres of the gas giants is driven by incident vacuum ultraviolet (VUV) light. Ethane is an important constituent in the atmospheres of the gas giants in our solar system. The present work describes translational spectroscopy studies of the VUV photochemistry of ethane using tuneable radiation in the wavelength range 112 ≤ λ ≤ 126 nm from a free electron laser and event-triggered, fast-framing, multi-mass imaging detection methods. Contributions from at least five primary photofragmentation pathways yielding CH2, CH3 and/or H atom products are demonstrated and interpreted in terms of unimolecular decay following rapid non-adiabatic coupling to the ground state potential energy surface. These data serve to highlight parallels with methane photochemistry and limitations in contemporary models of the photoinduced stratospheric chemistry of the gas giants. The work identifies additional photochemical reactions that require incorporation into next generation extraterrestrial atmospheric chemistry models which should help rationalise hitherto unexplained aspects of the atmospheric ethane/acetylene ratios revealed by the Cassini-Huygens fly-by of Jupiter.
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Affiliation(s)
- Yao Chang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
| | - Jiayue Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
| | - Zhichao Chen
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
| | - Zhiguo Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
- Key Laboratory of Functional Materials and Devices for Informatics of Anhui Higher Education Institutions, School of Physics and Electronic Engineering, Fuyang Normal University Fuyang Anhui 236041 China
| | - Yong Yu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
| | - Qingming Li
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
| | - Zhigang He
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
| | - Weiqing Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
| | - Rebecca A Ingle
- Department of Chemistry, University College London London WC1H 0AJ UK
| | - Matthew Bain
- School of Chemistry, University of Bristol Bristol BS8 1TS UK
| | | | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences 457 Zhongshan Road Dalian 116023 China
- Department of Chemistry, Southern University of Science and Technology Shenzhen 518055 China
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Tang YN, Yeh CT. Photolysis of Spiropentane with Xenon Resonance Line. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.197800004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Stepukhovich AD, Babayan VI. Intramolecular Rearrangements of Hydrocarbon Radicals in the Gas Phase. RUSSIAN CHEMICAL REVIEWS 2007. [DOI: 10.1070/rc1972v041n09abeh002090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wojciechowski K. The mechanism and kinetics of energy transfer processes in the Xe–CCl4–M (M=CH4, C2H2, C2H4, C2H6 C3H6 and C3H8) mixtures irradiated by xenon resonance light. Radiat Phys Chem Oxf Engl 1993 1998. [DOI: 10.1016/s0969-806x(97)00302-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Rowntree P, Dugal PC, Hunting D, Sanche L. Electron Stimulated Desorption of H2 from Chemisorbed Molecular Monolayers. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp9521159] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- P. Rowntree
- Département de chimie, Université de Sherbrooke, J1K 2R1 Sherbrooke, Québec, Canada, and MRC Group of Radiation Sciences, Département de Médecine Nucléaire et de Radiobiologie, Université de Sherbrooke, J1H 5N4 Sherbrooke, Québec Canada
| | - P.-C. Dugal
- Département de chimie, Université de Sherbrooke, J1K 2R1 Sherbrooke, Québec, Canada, and MRC Group of Radiation Sciences, Département de Médecine Nucléaire et de Radiobiologie, Université de Sherbrooke, J1H 5N4 Sherbrooke, Québec Canada
| | - D. Hunting
- Département de chimie, Université de Sherbrooke, J1K 2R1 Sherbrooke, Québec, Canada, and MRC Group of Radiation Sciences, Département de Médecine Nucléaire et de Radiobiologie, Université de Sherbrooke, J1H 5N4 Sherbrooke, Québec Canada
| | - L. Sanche
- Département de chimie, Université de Sherbrooke, J1K 2R1 Sherbrooke, Québec, Canada, and MRC Group of Radiation Sciences, Département de Médecine Nucléaire et de Radiobiologie, Université de Sherbrooke, J1H 5N4 Sherbrooke, Québec Canada
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Balamuta J, Golde MF, Ho Y. Product distributions in the reactions of excited noble‐gas atoms with hydrogen‐containing compounds. J Chem Phys 1983. [DOI: 10.1063/1.446103] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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A theoretical study of the photolytic decomposition of ethane ethylene via a triplet-state ethylidene intermediate. Chem Phys Lett 1978. [DOI: 10.1016/0009-2614(78)84007-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Richartz A, Buenker RJ, Bruna PJ, Peyerimhoff SD. Stability and structure of the C2H6+ion: investigation of the photoelectron spectrum of ethane below 14 eV usingab initiomethods. Mol Phys 1977. [DOI: 10.1080/00268977700101121] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Sandorfy C. Rydberg and Valence-Shell Transitions and the Photochemical Primary Steps in Saturated Organic Molecules. ACTA ACUST UNITED AC 1976. [DOI: 10.1524/zpch.1976.101.1-6.307] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Ausloos P, Rebbert R, Lias S. Primary processes in the photolysis of propane: the use of HI as a radical scavenger. ACTA ACUST UNITED AC 1974. [DOI: 10.1016/0047-2670(73)80024-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kawasaki M, Ibuki T, Iwasaki M, Takezaki Y. Vacuum‐ultraviolet photolysis of ethylene oxide. J Chem Phys 1973. [DOI: 10.1063/1.1680294] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Akimoto H, Obi K, Tanaka I. Application of the RRKM Theory to Energized Ethylene Formed in the Vacuum-ultraviolet Photolysis ofn-Paraffins. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1973. [DOI: 10.1246/bcsj.46.2267] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Obi K, Akimoto H, Ogata Y, Tanaka I. Photolyses of Propane, n‐Butane, and Cyclobutane at Xe and Kr Resonance Lines. J Chem Phys 1971. [DOI: 10.1063/1.1676667] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ogata Y, Obi K, Akimoto H, Tanaka I. The Decomposition of Energized Ethylene Formed in the Photolyses of Alkanes. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1971. [DOI: 10.1246/bcsj.44.2671] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ausloos P, Rebbert RE, Sieck LW. Ion–Molecule Reactions in the Radiolysis of Ethane. J Chem Phys 1971. [DOI: 10.1063/1.1675220] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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