赝势
吸附
化学
放松(心理学)
密度泛函理论
解吸
热脱附
原子物理学
物理化学
分子物理学
化学物理
计算化学
心理学
社会心理学
物理
作者
Jacek Goniakowski,M. J. Gillan
出处
期刊:Surface Science
[Elsevier]
日期:1996-04-01
卷期号:350 (1-3): 145-158
被引量:232
标识
DOI:10.1016/0039-6028(95)01252-4
摘要
First-principles calculations based on density functional theory and the pseudopotential method have been used to investigate the energetics of H2O adsorption on the (110) surface of TiO2 and SnO2. Full relaxation of all atomic positions is performed on slab systems with periodic boundary conditions, and cases of full and half coverage are studied. Both molecular and dissociative (H2O→OH−+H−) adsorption are treated, and allowance is made for relaxation of the adsorbed species to unsymmetrica configurations. It is found that for both TiO2 and SnO2 an unsymmetrical dissociated configuration is the most stable. The symmetrical molecularly adsorbed configuration is unstable with respect to lowering of symmetry, and is separated from the fully dissociated configuration by at most a very small energy barrier. The calculated dissociative adsorption energies for TiO2 and SnO2 are in reasonable agreement with the results of thermal desorption experiments. Calculated total and local electronic densities of states for dissociatively and molecularly adsorbed configurations are presented, and their relation with experimental UPS spectra is discussed.
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