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Quantum mechanical treatment for the diffusion process of a hydrogen atom on the amorphous water ice surface
Author(s) -
Takahashi Junko,
Nagaoka Masataka,
Masuda Koichi
Publication year - 1998
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1998)70:2<379::aid-qua15>3.0.co;2-7
Subject(s) - hydrogen atom , amorphous ice , amorphous solid , diffusion , hydrogen , atom (system on chip) , quantum , diffusion process , chemical physics , surface (topology) , process (computing) , materials science , atomic physics , physics , chemistry , thermodynamics , quantum mechanics , crystallography , computer science , geometry , group (periodic table) , embedded system , knowledge management , innovation diffusion , mathematics , operating system
The diffusion process of a hydrogen atom on the amorphous water ice surface was investigated under very low temperature conditions (10 and 70 K) using both classical and quantum approaches. The model amorphous water ice slab was prepared by the classical molecular dynamics (MD) simulation under the two‐dimensional periodic boundary condition with 1000 water molecules in a unit cell. For a H atom thrown onto the surface of the amorphous ice, the sticking and diffusion processes were studied. In the sticking case, the incident H atom initially diffused for 1–3 ps and then became trapped in one of the stable sites on the amorphous ice surface. To estimate the quantum mechanical diffusion constant, a new formalism was developed using the differential diffusion constant. A rate calculation for a H atom diffusing from one trapped site to another on the amorphous water ice was performed. The numerical value was compared with the hopping rate constant for the classical thermal diffusion, and a large quantum effect was found. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 379–385, 1998