DENSITY-FUNCTIONAL CALCULATION OF ELECTRONIC FRICTION OF IONS AND ATOMS ON METAL-SURFACES

The electronic friction of ions and atoms adsorbed on metal surfaces i s calculated within the time-dependent density-functional approach. Th e metal is described within the jellium model and the nonlocal, short- wavelength response of the surface electrons is treated by using the a diabatic local-density approximation. The electronic friction is found to be considerably larger than in previous estimates that were based on not fully consistent descriptions of the creation of low-frequency electron-hole pairs. For Xe on Ag the friction parameter is eta(parall el to)approximate to 3.4x10(8) s(-1) in good agreement with the Values derived from quartz-crystal microbalance and surface resistivity meas urements. These results confirm earlier suggestions concerning the imp ortant role of electronic processes in friction phenomena on metal sur faces.