Interaction ofAr17+ions on metallic surfaces at grazing incidence

The interaction of ${\mathrm{Ar}}^{17+}$ ions on metallic surfaces has been studied at various incidence angles by looking at the x rays emitted in flight by the ions with a crystal spectrometer. A model has been developed to describe the behavior of the ions outside the surface, and Dirac-Fock calculations of the Auger rates for states with many electrons in high-n states have been performed. The formation of hollow atoms outside the surface, in high-n states, has been observed at grazing incidence, in contrast to the hollow atoms formed below the surface in lower-n states (n=3–4). The decay to the ground state of these very excited ions outside the surface represents less than 1% of the overall decays.