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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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2
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Couturier-Tamburelli I, Danger G, Mouzay J, Pardanaud C, Piétri N. Titan's Organic Residue from Benzene Ices: Role of Atmospheric Pressure. J Phys Chem A 2024; 128:636-645. [PMID: 38194264 DOI: 10.1021/acs.jpca.3c06216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Benzene has been detected in Titan's atmosphere, the Saturn's largest moon, and it is known to condense when it reaches the stratosphere to form ice, which is submitted to low ultraviolet (UV) radiation. In a previous work, we put in evidence that the irradiation of benzene ice at λ > 230 nm induces the formation of volatile photoproducts, in particular, fulvene (a benzene isomer) and a solid residue. In this work, we study the influence of pressure on the residue formation after benzene ice's irradiation and its characterization using infrared (IR), Raman, and gas chromatography-mass spectrometry (GC-MS) methods. We show that the residue obtained during the increase of temperature performed at 1 mbar is dominated by CH sp2 groups, whereas the one obtained at 10-6 mbar contains an equivalent proportion of CH sp2 and sp3. Polyphenyls with up to three rings are unambiguously identified by GC-MS in all of the residues formed.
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Affiliation(s)
| | - G Danger
- Aix-Marseille Université, CNRS, PIIM, UMR 7345, 13397 Marseille, France
| | - J Mouzay
- Aix-Marseille Université, CNRS, PIIM, UMR 7345, 13397 Marseille, France
| | - C Pardanaud
- Aix-Marseille Université, CNRS, PIIM, UMR 7345, 13397 Marseille, France
| | - N Piétri
- Aix-Marseille Université, CNRS, PIIM, UMR 7345, 13397 Marseille, France
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3
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Wang ZC, Li YK, He SG, Bierbaum VM. Reactivity of amino acid anions with nitrogen and oxygen atoms. Phys Chem Chem Phys 2018; 20:4990-4996. [DOI: 10.1039/c7cp07886b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gas-phase reaction of deprotonated tyrosine with a ground state O atom generates five ionic products.
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Affiliation(s)
- Zhe-Chen Wang
- Department of Chemistry and Biochemistry
- University of Colorado
- Boulder
- Colorado 80309
- USA
| | - Ya-Ke Li
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing
- China
- University of Chinese Academy of Sciences
| | - Sheng-Gui He
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing
- China
| | - Veronica M. Bierbaum
- Department of Chemistry and Biochemistry
- University of Colorado
- Boulder
- Colorado 80309
- USA
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4
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Wang ZC, Bierbaum VM. Experimental and Computational Studies of the Reactions of N and O Atoms with Small Heterocyclic Anions. J Phys Chem A 2017; 121:3655-3661. [DOI: 10.1021/acs.jpca.7b02903] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhe-Chen Wang
- Department of Chemistry
and
Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Veronica M. Bierbaum
- Department of Chemistry
and
Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
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5
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Wang ZC, Bierbaum VM. Reactions of substituted benzene anions with N and O atoms: Chemistry in Titan’s upper atmosphere and the interstellar medium. J Chem Phys 2016; 144:214304. [DOI: 10.1063/1.4952454] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Zhe-Chen Wang
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Veronica M. Bierbaum
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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Hargreaves RJ, Buzan E, Dulick M, Bernath PF. High-resolution absorption cross sections of C2H6 at elevated temperatures. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.molap.2015.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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7
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Wang ZC, Cole CA, Demarais NJ, Snow TP, Bierbaum VM. Reactions of Azine Anions with Nitrogen and Oxygen Atoms: Implications for Titan’s Upper Atmosphere and Interstellar Chemistry. J Am Chem Soc 2015; 137:10700-9. [DOI: 10.1021/jacs.5b06089] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhe-Chen Wang
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Callie A. Cole
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Nicholas J. Demarais
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Theodore P. Snow
- Department
of Astrophysical and Planetary Sciences, University of Colorado, Boulder, Colorado 80309, United States
- Center
for Astrophysics and Space Astronomy, University of Colorado, Boulder, Colorado 80309, United States
| | - Veronica M. Bierbaum
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States
- Center
for Astrophysics and Space Astronomy, University of Colorado, Boulder, Colorado 80309, United States
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Sebree JA, Stern JC, Mandt KE, Domagal-Goldman SD, Trainer MG. 13C and 15N fractionation of CH 4/N 2 mixtures during photochemical aerosol formation: Relevance to Titan. ICARUS 2015; 270:421-428. [PMID: 31068732 PMCID: PMC6501594 DOI: 10.1016/j.icarus.2015.04.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The ratios of the stable isotopes that comprise each chemical species in Titan's atmosphere provide critical information towards understanding the processes taking place within its modern and ancient atmosphere. Several stable isotope pairs, including 12C/13C and 14N/15N, have been measured in situ or probed spectroscopically by Cassini-borne instruments, space telescopes, or through ground-based observations. Current attempts to model the observed isotope ratios incorporate fractionation resulting from atmospheric diffusion, hydrodynamic escape, and primary photochemical processes. However, the effect of a potentially critical pathway for isotopic fractionation - organic aerosol formation and subsequent deposition onto the surface of Titan - has not been considered due to insufficient data regarding fractionation during aerosol formation. To better understand the nature of this process, we have conducted a laboratory study to measure the isotopic fractionation associated with the formation of Titan aerosol analogs, commonly referred to as 'tholins', via far-UV irradiation of several methane (CH4) and dinitrogen (N2) mixtures. Analysis of the δ13C and δ15N isotopic signatures of the photochemical aerosol products using an isotope ratio mass spectrometer (IRMS) show that fractionation direction and magnitude are dependent on the initial bulk composition of the gas mixture. In general, the aerosols showed enrichment in 13C and 14N, and the observed fractionation trends can provide insight into the chemical mechanisms controlling photochemical aerosol formation.
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Affiliation(s)
- Joshua A. Sebree
- University of Northern Iowa, Department of Chemistry and Biochemistry, Cedar Falls, IA 50614, USA
- NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD 20771, USA
| | - Jennifer C. Stern
- NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD 20771, USA
| | - Kathleen E. Mandt
- Space Science and Engineering Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, USA
| | | | - Melissa G. Trainer
- NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD 20771, USA
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9
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Li C, Zhang X, Gao P, Yung Y. VERTICAL DISTRIBUTION OF
C
3
-HYDROCARBONS IN THE STRATOSPHERE OF TITAN. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/2041-8205/803/2/l19] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Peng Z, Carrasco N, Pernot P. Modeling of synchrotron-based laboratory simulations of Titan’s ionospheric photochemistry. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.grj.2014.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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11
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Villa M, Senent ML, Carvajal M. Highly correlated ab initio study of the low frequency modes of propane and various monosubstituted isotopologues containing D and 13C. Phys Chem Chem Phys 2013; 15:10258-69. [PMID: 23604056 DOI: 10.1039/c3cp50213a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
With the purpose of providing some clues that could encourage the spectral recordings of propane and various monodeuterated and (13)C isotopologues and also to explore their far infrared spectra at low temperatures, the energy levels corresponding to their three lowest frequency modes are determined variationally using a flexible model in three dimensions. Five vibrationally corrected potential energy surfaces are computed using CCSD(T) ab initio calculations. In spite of the quality of these highly correlated potentials in molecules with similar structures, it was proven that an empirical adjustment of the surfaces would enclose accurately the experimental and theoretical frequency residuals and therefore it is also used in the present work. Interacting terms, energy levels and tunneling splittings are provided for CH3CH2CH3, CH3(13)CH2CH3, (13)CH3CH2CH3, CH2DCH2CH3 and CH3CHDCH3. Infrared and Raman transitions of CH3CH2CH3 are assigned. Correlation between symmetry species of the five isotopologue symmetry groups (G36, G36, G18, G6 and G'18, respectively) is established for the classification of the levels and torsional splittings. The rotational constants are determined with CCSD(T)/CBS (A0 = 29263.46 MHz, B0 = 8454.10 MHz and C0 = 7466.64 MHz) using a non-relativistic procedure. Fundamental anharmonic frequencies corresponding to the high and medium amplitude modes are computed for all the isotopologues. The adjusted parameters are accurate enough to be employed in further spectral analysis.
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Affiliation(s)
- M Villa
- Departamento de Química, UAM-I Purísima y Michoacan, s/n, CP 09340, Mexico DF, Mexico.
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Trixler F. Quantum Tunnelling to the Origin and Evolution of Life. CURR ORG CHEM 2013; 17:1758-1770. [PMID: 24039543 PMCID: PMC3768233 DOI: 10.2174/13852728113179990083] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 06/13/2013] [Accepted: 06/13/2013] [Indexed: 11/29/2022]
Abstract
Quantum tunnelling is a phenomenon which becomes relevant at the nanoscale and below. It is a paradox from the classical point of view as it enables elementary particles and atoms to permeate an energetic barrier without the need for sufficient energy to overcome it. Tunnelling might seem to be an exotic process only important for special physical effects and applications such as the Tunnel Diode, Scanning Tunnelling Microscopy (electron tunnelling) or Near-field Optical Microscopy operating in photon tunnelling mode. However, this review demonstrates that tunnelling can do far more, being of vital importance for life: physical and chemical processes which are crucial in theories about the origin and evolution of life can be traced directly back to the effects of quantum tunnelling. These processes include the chemical evolution in stellar interiors and within the cold interstellar medium, prebiotic chemistry in the atmosphere and subsurface of planetary bodies, planetary habitability via insolation and geothermal heat as well as the function of biomolecular nanomachines. This review shows that quantum tunnelling has many highly important implications to the field of molecular and biological evolution, prebiotic chemistry and astrobiology.
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Affiliation(s)
- Frank Trixler
- Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Schellingstraße 4, 80799 München, Germany; ; Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Theresienstrasse 41, 80333, München, Germany; ; TUM School of Education, Technische Universität München, Museumsinsel 1, 80538 München, Germany
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13
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Blitz MA, Seakins PW. Laboratory studies of photochemistry and gas phase radical reaction kinetics relevant to planetary atmospheres. Chem Soc Rev 2012; 41:6318-47. [DOI: 10.1039/c2cs35204d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Atreya SK. The significance of trace constituents in the solar system. Faraday Discuss 2011; 147:9-29; discussion 83-102. [PMID: 21302540 DOI: 10.1039/c005460g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Trace or minor constituents are key to the origin, maintenance, and the eventual fate of atmospheres of solar system objects. In this Introductory Paper, I illustrate this point by discussing certain cross cutting themes, including the chemistry of the formation and stability of a nitrogen atmosphere on Titan and the Earth, the chemical and biochemical origin of methane on the terrestrial planets and Titan, production and role of photochemical haze and aerosols, especially on Titan, and the significance of electro-photochemistry for habitability of Mars.
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Affiliation(s)
- Sushil K Atreya
- Department of Atmospheric, Oceanic, and Space Sciences Space Research Building, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA
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15
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Haas JR. The potential feasibility of chlorinic photosynthesis on exoplanets. ASTROBIOLOGY 2010; 10:953-963. [PMID: 21118026 DOI: 10.1089/ast.2009.0364] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The modern search for life-bearing exoplanets emphasizes the potential detection of O(2) and O(3) absorption spectra in exoplanetary atmospheres as ideal signatures of biology. However, oxygenic photosynthesis may not arise ubiquitously in exoplanetary biospheres. Alternative evolutionary paths may yield planetary atmospheres tinted with the waste products of other dominant metabolisms, including potentially exotic biochemistries. This paper defines chlorinic photosynthesis (CPS) as biologically mediated photolytic oxidation of aqueous Cl(-) to form halocarbon or dihalogen products, coupled with CO(2) assimilation. This hypothetical metabolism appears to be feasible energetically, physically, and geochemically, and could potentially develop under conditions that approximate the terrestrial Archean. It is hypothesized that an exoplanetary biosphere in which chlorinic photosynthesis dominates primary production would tend to evolve a strongly oxidizing, halogen-enriched atmosphere over geologic time. It is recommended that astronomical observations of exoplanetary outgoing thermal emission spectra consider signs of halogenated chemical species as likely indicators of the presence of a chlorinic biosphere. Planets that favor the evolution of CPS would probably receive equivalent or greater surface UV flux than is produced by the Sun, which would promote stronger abiotic UV photolysis of aqueous halides than occurred during Earth's Archean era and impose stronger evolutionary selection pressures on endemic life to accommodate and utilize halogenated compounds. Ocean-bearing planets of stars with metallicities equivalent to, or greater than, the Sun should especially favor the evolution of chlorinic biospheres because of the higher relative seawater abundances of Cl, Br, and I such planets would tend to host. Directed searches for chlorinic biospheres should probably focus on G0-G2, F, and A spectral class stars that have bulk metallicities of +0.0 Dex or greater.
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Affiliation(s)
- Johnson R Haas
- Department of Geosciences, Western Michigan University, Kalamazoo, Michigan 49008, USA.
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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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17
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Kaiser RI, Maksyutenko P, Ennis C, Zhang F, Gu X, Krishtal SP, Mebel AM, Kostko O, Ahmed M. Untangling the chemical evolution of Titan's atmosphere and surface–from homogeneous to heterogeneous chemistry. Faraday Discuss 2010; 147:429-78; discussion 527-52. [DOI: 10.1039/c003599h] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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