Wave packet propagation study of the electron transfer in back-scattering of H^- ions from alkali adsorbates on an Al surface

The charge transfer between an H^- ion and a free-electron metal surface with a single alkali adsorbate (Li and Cs) is studied with the wave packet propagation approach in the back-scattering geometry. Both the static problem for a fixed projectile-surface distance and the problem of charge transfer during a collision are considered. The three body (projectile-adsorbate-surface) aspect of the charge transfer process in this case results in an avoided crossing between the projectile and adsorbate-localized quasi-stationary states. We analyze and discuss the local effect of the adsorbate on the resonant charge transfer and the applicability of the rate equation approach.