Auger transition rates for the neutralization of He+ ions in front of an aluminium surface

In a detailed analysis of image charge effects on the trajectories of He+ ions with keV energies scattered from a clean Al(111) surface under a grazing angle of incidence we find evidence for contributions from two different Auger processes. From our data we derive Auger neutralization rates for the filling of the Is hole and the Auger deexcitation rate for the 2s S-3 level as function of the distance from the surface. The rates are obtained from the experiments in a straightforward manner and can be considered as a profound basis for the comparison with theoretical calculations. (C) 1998 Elsevier Science B.V. All rights reserved.