AUGER INTRA-ATOMIC TRANSITIONS IN GRAZING ATOM-SURFACE COLLISIONS

The intra-atomic transitions involving bound states of an ion or an atom moving parallel to a solid surface are analyzed using linear-response theory. Different models have been employed to describe the response of the medium. The velocity dependence of excitation and deexcitation processes is studied. Numerical calculations are presented for transitions involving Is and 2p hydrogenic states. The highest deexcitation rate is obtained when a 2p orbital is oriented in the direction normal to the surface. Numerical results are given for hydrogen atoms moving near aluminum. The decay of the deexcitation rate, which scales following a power law of the distance to the surface, proves to be almost independent of the velocity when upsilon < 2 a.u. The excitation probability is about two orders of magnitude below the deexcitation probability. Finally, the effect of the energy shift and splitting of the atomic states originating in the interaction with the valence-band electrons has been studied in detail.