摘要：Recent advances in a series of studies based on the molecular dynamics (MD) computer simulation that was performed to investigate the whole of H 2 formation process on the surface of dust grains throughout within a single model are reviewed. Amorphous water ice slabs were generated at 10 K and 70 K as a model surface of dust grains, and then the first and second incident H atoms were thrown onto the surface. The following fundamental processes of H 2 formation via two H atoms’ recombination, H H → H 2 , were studied in detail; 1) the sticking of H atom onto the surface, 2) the diffusion of H atom on the surface, 3) the reaction of two H atoms on the surface, 4) the ejection of H 2 from the ice surface. The sticking probability, the mobility, the reaction probability, and the ejection lifetime were selfconsistantly obtained for the above processes. The product energy distribution of H 2 molecules formed on icy mantles of dust grains was also studied, and it was found that H 2 molecules can be highly vibrationally excited by formation pumping mechanism.
