Formation and filling of hollow Ne atoms below an Al surface

Dynamic properties of hollow Ne atoms moving in shallow layers of an Al(111) solid were studied using the method of Auger spectroscopy. The K and L Auger electrons of the projectiles were measured for various impact energies in the range of 0.1-22.5 keV. Structures in the Auger spectra are reanalyzed by means of theoretical KLL Auger energies including solid-state effects. For projectile energies below 1 keV the structure of the KLL maximum changes significantly with the impact energy due to the onset of the charge transfer cross sections between target and projectile L shell. The data were interpreted by an extension of our previously developed cascade model providing specific information about the filling state of the hollow atom during the K Auger transition. In addition L Anger intensities measured in a wide projectile energy range are theoretically reproduced. The separation of the different processes which occur during the electron emission allows us to verify the importance of the capture process and the L Auger process. Finally, the depth of the L and K Auger emission is determined in the projectile range studied.