STICKING PROBABILITY OF H AND D ATOMS ON AMORPHOUS ICE - A COMPUTATIONAL STUDY

Sticking of H and D atoms on amorphous ice was studied computationally, using the molecular dynamics simulation technique. A simple formula S(T) = [(k(B) T/E0) + 1]-2 was obtained for the sticking probability at T(gas) less-than-or-similar-to 300 K, with E0 = 200 K for the D atom, E0 = 102 K for the H atom. The formula is suggested as a reasonable estimate for sticking on dust grains in general-if most grains are covered by at least a few layers of weakly bonded disordered molecular material.