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Abstract
The kinetic Monte Carlo method, used in astrochemistry to investigate suprathermal (hot) particles at the molecular level, is presented. Different modifications of this method, aimed at studying the influence of suprathermal particles in the processes occurring in gas and dust envelopes surrounding astrophysical objects — prestellar and protostellar cores of molecular clouds, planets, their moons, and comets in the Solar and extrasolar planetary systems — are considered. The important role of the fraction of suprathermal particles in astrochemical applications of this approach is demonstrated. The presence of these particles leads to local changes in the chemical composition; causes non-thermal emissions in gas and dust envelopes; enhances the chemical exchange between the gas and dust fractions of envelope; leads to the formation of extended hot coronae of planets; increases non-thermal atmospheric losses, thus determining the evolution of planetary atmosphere on astronomical time scales; and facilitates the formation of complex molecules in gas and dust envelopes of astrophysical objects.
The bibliography includes 146 references.
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Gröller H, Shematovich VI, Lichtenegger HIM, Lammer H, Pfleger M, Kulikov YN, Macher W, Amerstorfer UV, Biernat HK. Venus' atomic hot oxygen environment. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010je003697] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Thomas RD. When electrons meet molecular ions and what happens next: dissociative recombination from interstellar molecular clouds to internal combustion engines. MASS SPECTROMETRY REVIEWS 2008; 27:485-530. [PMID: 18618616 DOI: 10.1002/mas.20169] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The interaction of matter with its environment is the driving force behind the evolution of 99% of the observed matter in the universe. The majority of the visible universe exists in a state of weak ionization, the so called fourth state of matter: plasma. Plasmas are ubiquitous, from those occurring naturally; interstellar molecular clouds, cometary comae, circumstellar shells, to those which are anthropic in origin; flames, combustion engines and fusion reactors. The evolution of these plasmas is driven by the interaction of the plasma constituents, the ions, and the electrons. One of the most important subsets of these reactions is electron-molecular ion recombination. This process is significant for two very important reasons. It is an ionization reducing reaction, removing two ionised species and producing neutral products. Furthermore, these products may themselves be reactive radical species which can then further drive the evolution of the plasma. The rate at which the electron reacts with the ion depends on many parameters, for examples the collision energy, the internal energy of the ion, and the structure of the ion itself. Measuring these properties together with the manner in which the system breaks up is therefore critical if the evolution of the environment is to be understood at all. Several techniques have been developed to study just such reactions to obtain the necessary information on the parameters. In this paper the focus will be on one the most recently developed of these, the Ion Storage Ring, together with the detection tools and techniques used to extract the necessary information from the reaction.
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Affiliation(s)
- Richard D Thomas
- Department of Physics, Albanova University Centre, Stockholm University, S106 91 Stockholm, Sweden.
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Chaufray JY, Modolo R, Leblanc F, Chanteur G, Johnson RE, Luhmann JG. Mars solar wind interaction: Formation of the Martian corona and atmospheric loss to space. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2007je002915] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Cipriani F, Leblanc F, Berthelier JJ. Martian corona: Nonthermal sources of hot heavy species. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006je002818] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lammer H, Lichtenegger HIM, Kulikov YN, Griessmeier JM, Terada N, Erkaev NV, Biernat HK, Khodachenko ML, Ribas I, Penz T, Selsis F. Coronal mass ejection (CME) activity of low mass M stars as an important factor for the habitability of terrestrial exoplanets. II. CME-induced ion pick up of Earth-like exoplanets in close-in habitable zones. ASTROBIOLOGY 2007; 7:185-207. [PMID: 17407407 DOI: 10.1089/ast.2006.0128] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Atmospheric erosion of CO2-rich Earth-size exoplanets due to coronal mass ejection (CME)-induced ion pick up within close-in habitable zones of active M-type dwarf stars is investigated. Since M stars are active at the X-ray and extreme ultraviolet radiation (XUV) wave-lengths over long periods of time, we have applied a thermal balance model at various XUV flux input values for simulating the thermospheric heating by photodissociation and ionization processes due to exothermic chemical reactions and cooling by the CO2 infrared radiation in the 15 microm band. Our study shows that intense XUV radiation of active M stars results in atmospheric expansion and extended exospheres. Using thermospheric neutral and ion densities calculated for various XUV fluxes, we applied a numerical test particle model for simulation of atmospheric ion pick up loss from an extended exosphere arising from its interaction with expected minimum and maximum CME plasma flows. Our results indicate that the Earth-like exoplanets that have no, or weak, magnetic moments may lose tens to hundreds of bars of atmospheric pressure, or even their whole atmospheres due to the CME-induced O ion pick up at orbital distances <or=0.2 astronomical units. We have found that, when exposed to intense XUV fluxes, atmospheres with CO2/N2 mixing ratios lower than 96% will show an increase in exospheric temperatures and expanded thermosphere-exosphere environments. Hence, they suffer stronger atmospheric erosion, which can result in the total loss of several hundred bars even if an exoplanet is protected by a "magnetic shield" with its boundary located at 1 Earth radius above the surface. Furthermore, our study indicates that magnetic moments of tidally locked Earth-like exoplanets are essential for protecting their expanded upper atmospheres because of intense XUV radiation against CME plasma erosion. Therefore, we suggest that larger and more massive terrestrial-type exoplanets may better protect their atmospheres against CMEs, because the larger cores of such exoplanets would generate stronger magnetic moments and their higher gravitational acceleration would constrain the expansion of their thermosphere-exosphere regions and reduce atmospheric escape.
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Affiliation(s)
- Helmut Lammer
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria.
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Petrignani A, Hellberg F, Thomas RD, Larsson M, Cosby PC, van der Zande WJ. Electron energy-dependent product state distributions in the dissociative recombination of O2+. J Chem Phys 2005; 122:234311. [PMID: 16008445 DOI: 10.1063/1.1937388] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We present product state distributions and quantum yields from the dissociative recombination reaction of O2+ in its electronic and vibrational ground states as a function of electron collision energy between 0 and 300 meV. The experiments have been performed in the heavy-ion storage ring, CRYRING, and use a cold hollow-cathode discharge source for the production of cold molecular oxygen ions. The branching fractions over the different dissociation limits show distinct oscillations while the resulting product quantum yields are largely independent of electron collision energy above 40 meV. The branching results are well reproduced assuming an isotropic dissociation process, in contrast with recent theoretical predictions.
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Affiliation(s)
- Annemieke Petrignani
- FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ, Amsterdam, The Netherlands.
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Petrignani A, van der Zande WJ, Cosby PC, Hellberg F, Thomas RD, Larsson M. Vibrationally resolved rate coefficients and branching fractions in the dissociative recombination of O2+. J Chem Phys 2005; 122:14302. [PMID: 15638654 DOI: 10.1063/1.1825991] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have studied the dissociative recombination of the first three vibrational levels of O(2) (+) in its electronic ground X (2)Pi(g) state. Absolute rate coefficients, cross sections, quantum yields and branching fractions have been determined in a merged-beam experiment in the heavy-ion storage ring, CRYRING, employing fragment imaging for the reaction dynamics. We present the absolute total rate coefficients as function of collision energies up to 0.4 eV for five different vibrational populations of the ion beam, as well as the partial (vibrationally resolved) rate coefficients and the branching fractions near 0 eV collision energy for the vibrational levels v=0, 1, and 2. The vibrational populations used were produced in a modified electron impact ion source, which has been calibrated using Cs-O(2)(+) dissociative charge transfer reactions. The measurements indicate that at low collision energies, the total rate coefficient is weakly dependent on the vibrational excitation. The calculated thermal rate coefficient at 300 K decreases upon vibrational excitation. The partial rate coefficients as well as the partial branching fractions are found to be strongly dependent on the vibrational level. The partial rate coefficient is the fastest for v=0 and goes down by a factor of two or more for v=1 and 2. The O((1)S) quantum yield, linked to the green airglow, increases strongly upon increasing vibrational level. The effects of the dissociative recombination reactions and super elastic collisions on the vibrational populations are discussed.
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Affiliation(s)
- Annemieke Petrignani
- FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
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Fox JL. Response of the Martian thermosphere/ionosphere to enhanced fluxes of solar soft X rays. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2004ja010380] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sheehan CH. Dissociative recombination of N2+, O2+, and NO+: Rate coefficients for ground state and vibrationally excited ions. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003ja010132] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Seiersen K, Heber O, Jensen MJ, Safvan CP, Andersen LH. Dissociative recombination of dications. J Chem Phys 2003. [DOI: 10.1063/1.1579470] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Li X, Ng CY. Absolute charge transfer cross sections for the state-selected reactions O+(2D,2P)+O2. J Chem Phys 2003. [DOI: 10.1063/1.1547750] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Krasnopolsky VA. Mars' upper atmosphere and ionosphere at low, medium, and high solar activities: Implications for evolution of water. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/2001je001809] [Citation(s) in RCA: 188] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Affiliation(s)
- Cheuk-Yiu Ng
- Department of Chemistry, University of California at Davis, One Shields Ave., Davis, California 95616
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Fox JL, Sung KY. Solar activity variations of the Venus thermosphere/ionosphere. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001ja000069] [Citation(s) in RCA: 163] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Peverall R, Rosén S, Peterson JR, Larsson M, Al-Khalili A, Vikor L, Semaniak J, Bobbenkamp R, Le Padellec A, Maurellis AN, van der Zande WJ. Dissociative recombination and excitation of O2+: Cross sections, product yields and implications for studies of ionospheric airglows. J Chem Phys 2001. [DOI: 10.1063/1.1349079] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Merged-beams studies of electron-molecular ion interactions in ion storage rings. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s1071-9687(01)80008-3] [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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Andersen LH, Bilodeau R, Jensen MJ, Nielsen SB, Safvan CP, Seiersen K. Coulomb and centrifugal barrier bound dianion resonances of NO[sub 2]. J Chem Phys 2001. [DOI: 10.1063/1.1328380] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Kier LB, Cheng CK, Seybold PG. Cellular automata models of chemical systems. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2000; 11:79-102. [PMID: 10877471 DOI: 10.1080/10629360008039116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This paper describes the use of kinematic, asynchronous, stochastic cellular automata to model liquid properties, solution phenomena and kinetic phenomena encountered in complex biological systems. Cellular automata models of dynamic phenomena represent in silico experiments designed to assess the effects of competing factors on the physical and chemical properties of solutions and other complex systems. Specific applications include solution behavior, separation of immiscible liquids, micelle formation, diffusion, membrane passage, first- and second-order chemical kinetics, enzyme activity and acid dissociation. Cellular automata is thus considered as providing an exploratory method for the analysis of dynamic phenomena and the discovery and understanding of new, unexpected phenomena.
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Affiliation(s)
- L B Kier
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond 23298, USA
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Kim J, Nagy AF, Fox JL, Cravens TE. Solar cycle variability of hot oxygen atoms at Mars. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98ja02727] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Amitay Z, Baer A, Dahan M, Knoll L, Lange M, Levin J, Schneider IF, Schwalm D, Suzor-Weiner A, Vager Z, Wester R, Wolf A, Zajfman D. Dissociative recombination of HD+ in selected vibrational quantum states. Science 1998; 281:75-8. [PMID: 9651247 DOI: 10.1126/science.281.5373.75] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Rate coefficients for dissociative recombination of HD+ in selected vibrational states have been measured by a combination of two molecular fragment imaging methods by using the heavy-ion storage ring technique. Recombination fragment imaging yields state-to-state reaction rates. These rates are converted to rate coefficients by using vibrational level populations of the stored ion beam, derived from nuclear coordinate distributions measured on extracted ions. The results show strongly increasing rate coefficients for high vibrational excitation, where additional dissociation routes open up, in agreement with a theoretical calculation. Very low rate coefficients are found for certain, isolated vibrational states.
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Affiliation(s)
- Z Amitay
- Z. Amitay, A. Baer, M. Dahan, J. Levin, Z. Vager, D. Zajfman, Department of Particle Physics, Weizmann Institute of Science, Rehovot, 76100, Israel. L. Knoll, M. Lange, D. Schwalm, R. Wester, A. Wolf, Max-Planck-Institut fur Kernphysik and
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Skrzypkowski MP, Gougousi T, Johnsen R, Golde MF. Measurement of the absolute yield of CO(a 3Π)+O products in the dissociative recombination of CO2+ ions with electrons. J Chem Phys 1998. [DOI: 10.1063/1.476267] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Affiliation(s)
- Steven L. Guberman
- Institute for Scientific Research, 33 Bedford Street, Lexington, MA 02173, USA
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Fox JL, Hać A. Spectrum of hot O at the exobases of the terrestrial planets. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97ja02089] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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