Grain Surface Reactions in Molecular Clouds: The Effect of Cosmic Rays and Quantum Tunneling
Language
en
Article de revue
This item was published in
Monthly Notices of the Royal Astronomical Society. 2014, vol. 440, n° 4, p. 3557-3567
Oxford University Press (OUP): Policy P - Oxford Open Option A
English 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 ...Read more >
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.Read less <
Origin
Hal imported