EVOLUTION OF KLL-AUGER DECAY FROM N6-]AU(111) ABOVE THE FIRST LAYER()

Auger electrons originating in the interaction of N6+ ions with a Au(l ll) surface are measured. Solid-state effects acting on the ions as we ll as on the electrons are clearly detected although the experimental conditions guarantee emission only from above the top layer of target atoms. KLL electrons emitted from neutralized projectile states with l ow (n(L) = 2, i.e. hollow atom) and high (n(L) = 5, 6) L-shell populat ion can be distinguished. It is shown by Doppler shift analysis of the electron energies that the emission from hollow atom states occurs af ter the image acceleration of the projectile but before it is reflecte d by the surface, and the emission with filled L-shell after the refle ction. The angular distributions for both electron groups are differen t and depend on the ion energy. This is explained in terms of differen t height z at emission, by the effect of electron refraction by the z- dependent surface potential barrier.