Z1-oscillations in the stopping of slow ions during grazing ion-surface scattering

We have scattered ions with energies <10 keV/amu and atomic numbers Z(1) < 20 from an Al (1 1 1)-surface under grazing angles of incidence. From a study of the projectile energy loss as a function of angle of incidence we derive position dependent stopping powers which show pronounced oscillations with Z(1). Comparison of the stopping powers at different distances from the surface plane, i.e. for different electron densities, reveals characteristic shifts in those oscillatory structures as predicted by nonlinear density functional theory. (C) 1998 Elsevier Science B.V.