MOLECULAR-DYNAMICS STUDIES OF DISSOCIATION OF O-2 ON AG(111) SURFACE

Full dimensional molecular dynamics studies have been carried out with in a quantum-classical framework for the dissociation of O-2 on Ag(111 ). Couplings among three potential energy surfaces were included to re present the nonadiabatic character of the dynamics. The dissociation p robabilities (S-0) as a function of initial kinetic energies (E-i = 0. 1-1.0 eV), incident angles (theta(p)) are obtained. The surface temper ature effect is also investigated. The results reveal complicated init ial incident kinetic energy and surface temperature dependences of the O-2 dissociation on Ag(111). The simulation shows that the dissociati on is favoured for the incident O-2 parallel to the surface at 0.1 eV but perpendicular to the surface at 1.0 eV. This suggests that both pe roxo-like (O-2(2-)) and superoxo-like (O-2(-)) species may be present on Ag(111) but one dominates over the other at different incident ener gies. Comparisons with experiments and two dimensional calculations ar e made. (C) 1997 Elsevier Science B.V.