Charge exchange of fast metastable He-atoms in front of an Al(1 1 1) surface

Abstract

A beam of keV metastable He atoms is produced by the passage of He + ions through an alkali vapour target and scattered under a grazing angle of incidence from a clean and flat Al(1 1 1) surface. Charge exchange between atoms and surface is studied via the effect of image charge deflection on trajectories of scattered projectiles. The angular distributions for scattered atoms are analyzed in terms of electron transition rates which form the basis for a Monte-Carlo computer simulation. Resonant charge transfer plays a dominant role leading to an ionization of the metastable projectiles. The transition rates for this process are calculated by making use of the Coupled Angular Mode (CAM) method and dynamic properties of the interactions are taken into account by translational factors connecting the projectile and metal frames of reference.