Electron dynamics at surfaces induced by highly charged ions

Energy spectra of electrons resulting from hydrogen-like multiply charged N6+ and Q(7+) ions on various surfaces are presented and discussed. Por metal target surfaces thr formation and decay of hollow atoms during the approach towards the surface is rather well understood in terms of the classical over-the-barrier model. Measurements with insulating LiF surfaces and conducting LiF covered Au(1 1 1) surfaces on the other hand indicate that in these cases hollow atom formation is delayed or inhibited at all. This implies that the potential energy of the multiply charged projectiles is carried directly into the surface.