Auger spectra from highly insulating samples (AI,O, , Si,N,) are collected in a gaseous environment. It is demonstrated that the build-up of negative surface charge can be reduced considerably under suitable conditions. It is proposed that the decharging of the surface is initiated by Auger neutralization of the ions formed in the gaseous environment in coUisioas with the primary keV electrons.

Abstract. The orientation and alignment of Li(2p) excited in 1-2.5 keV Li + collisions with He and Ar, and of Na(3p) excited in 2.5keV Na ÷ collisions with He and Ne have been studied by the polarized photon-scattered particle coincidence technique. The covered range of scattering angles is between 1 and 18 degrees. The data are presented in terms of the alignment angle 7 and the transferred angular momentum LQ A qualitative analysis of the data is attempted on the basis of diabatic molecular orbital diagrams for the studied collisions systems.