Review of OCS gas-phase reactions in dark cloud chemical models

Jean-Christophe Loison 1 Philippe Halvick Astrid Bergeat 2, 3 Kevin M. Hickson 1 Valentine Wakelam 4
4 AMOR 2012
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
Abstract : The association reaction S + CO {\to} OCS + hnu has been identified as being particularly important for the prediction of gas-phase OCS abundances by chemical models of dark clouds. We performed detailed ab-initio calculations for this process in addition to undertaking an extensive review of the neutral-neutral reactions involving this species which might be important in such environments. The rate constant for this association reaction was estimated to be several orders of magnitude smaller than the one present in current astrochemical databases. The new rate for this reaction and the introduction of other processes, notably OH + CS {\to} OCS + H and C + OCS {\to} CO + CS, dramatically changes the OCS gas-phase abundance predicted by chemical models for dark clouds. The disagreement with observations in TMC-1 (CP) and L134N (N), suggests that OCS may be formed on grain surfaces as is the case for methanol. The observation of solid OCS on interstellar ices supports this hypothesis.
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Article dans une revue
Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2012, 421 (2), pp.1476-1484. 〈10.1111/j.1365-2966.2012.20412.x〉
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https://hal.archives-ouvertes.fr/hal-00665009
Contributeur : Marie-Paule Pomies <>
Soumis le : mercredi 1 février 2012 - 08:12:00
Dernière modification le : mercredi 27 juillet 2016 - 14:48:48

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Jean-Christophe Loison, Philippe Halvick, Astrid Bergeat, Kevin M. Hickson, Valentine Wakelam. Review of OCS gas-phase reactions in dark cloud chemical models. Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2012, 421 (2), pp.1476-1484. 〈10.1111/j.1365-2966.2012.20412.x〉. 〈hal-00665009〉

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