X ray spectroscopy of highly charged ions interacting with surfaces

Abstract

The interaction of highly charged ions on surfaces has been studied at various incidence angles by looking at the X rays emitted in flight by the ions with a crystal spectrometer. This paper is focused on the study of the decay between the L and K shell which is mainly an Auger process for highly charged ions like Ar17+. A model has been developed to describe the behaviour of the ions outside the surface,a nd Dirac‐Fock calculations of the Auger rates for states with many electrons in high n states have been performed. The formation of highly excited hollow atoms, outside the surface, has been observed, at grazing incidence. The signature of these superexcited ions only represents a few % of the overall observed decays.In addition experiments were performed with very thin targets (20–20000 Å) to study the influence of their thickness on the X ray emission. This allows a direct measurement of the lifetime of the hollow atoms inside the solid, which has been found to be less than 8 10−16 s.