Grain Surface Reactions in Molecular Clouds: The Effect of Cosmic Rays and Quantum Tunneling

L. Reboussin 1 Valentine Wakelam 1 S. Guilloteau 1 F. Hersant 2
1 AMOR 2014
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
2 FORMATION STELLAIRE 2014
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 : Grain-surface reactions play an essential role in interstellar chemistry, since dust grain catalyses reactions at its surface allowing for the formation of molecules. We used a chemical model in which both gas-phase and grain-surface reactions occur and studied particularly the diffusion mechanisms on the surface of the grains. Surface reactions can occur via thermal hopping when species cross over a potential barrier or via quantum tunneling when species cross through this barrier. We show that the thermal diffusion (hopping) can be much more efficient after a cosmic ray particle collides with a dust grain, heating it to a peak temperature of 70K. We present here the results of numerical simulations after including the quantum tunneling mechanism for species H, H2 and O and considering the effect of cosmic ray particle collision on the surface reactions. As a consequence, the gas-phase and grain-surface abundances are affected and we show that more complex molecules can be formed in molecular clouds.
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Soumis le : lundi 24 mars 2014 - 09:02:02
Dernière modification le : mercredi 29 novembre 2017 - 15:00:29

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L. Reboussin, Valentine Wakelam, S. Guilloteau, F. Hersant. Grain Surface Reactions in Molecular Clouds: The Effect of Cosmic Rays and Quantum Tunneling. Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2014, 440 (4), pp.3557-3567. 〈10.1093/mnras/stu462〉. 〈hal-00964074〉

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