ELECTRONIC DISTORTION IN KEV PARTICLE BOMBARDMENT

The angle resolved velocity distributions of excited (F-4(7/2)) and ground state (F-4(9/2)) Rh atoms ejected from the Rh {100} surface due to keV Ar+ ion bombardment are described with; a-model that takes into account the local electronic environment. The lifetime of the;e excitation probability for each excited Rh atom is assumed to depend on the local embedded-atom method (EAM) density. It is thus possible to distinguish between ejected atoms that experience very little difference in their electronic environments, Although most excited atoms that survive with significantly high excitation probabilities originate from-the surface layer, it is not uncommon for an atom beneath the surface to eject from a disrupted environment and end up with a high excitation probability. This model improves upon a previous one, where the lifetime was assumed to vary with the height above the original surface.