EXTENDED CLASSICAL OVER-BARRIER MODEL FOR COLLISIONS OF HIGHLY-CHARGED IONS WITH CONDUCTING AND INSULATING SURFACES

We have extended the classical over-barrier model to simulate the neut ralization dynamics of highly charged ions interacting under grazing i ncidence with conducting and insulating surfaces. Our calculations are based on simple model rates for resonant and Auger transitions. We in clude effects caused by the dielectric response of the target and, for insulators, localized surface charges. Characteristic deviations rega rding the charge-transfer processes from conducting and insulating tar gets to the ion are discussed. We find good agreement with previously published experimental data for the image energy gain of a variety of highly charged ions impinging on Au, Al, LiF, and KI crystals. [S1050- 2947(98)01001-4].