Auger neutralization and ionization in grazing ion-surface interaction

The effect of the projectile velocity parallel to the surface vparallel on Auger-type neutralization and ionization processes during grazing scattering of atomic particles from surfaces will be discussed. It is found that, contrary to the static case (vparallel=0), under grazing collision the Auger-type electron exchange between the metallic conduction band and an atomic orbital is a two-way process: atomic particles may be neutralized, as well as ionized. In particular, two types of vparallel dependence are obtained: (1) a gradual decrease of the final atomic level population with increasing vparallel in the case of atomic levels below the Fermi level EF, and (2) a peak-shaped vparallel dependence for atomic levels above EF. The leading features of these basic electron-exchange mechanisms between atoms and surfaces are illustrated for various atomic quasi-one-electron systems scattered from silver and magnesium surfaces. (orig.)