ELECTRON-CAPTURE PROCESSES IN AUTOIONIZING-STATE PRODUCTION IN ION-SURFACE SCATTERING

Results of a study of the formation of doubly excited autoionising sta tes in singly and doubly charged inert gas ion collisions with Mg and Al surfaces are presented. In case of Ar++ ion scattering with a Mg su rface, formation of such states is observed as a result of electron ca pture as the ion approaches the surface. This is not observed in case of Ne++ scattering on Mg where these excited states result from a viol ent binary collision with Mg surface atoms. In case of Ne++ scattering on Al both mechanisms are observed. These results are interpreted in terms of a numerical model which considers a series of Auger and reson ant decay and capture processes.