The electronic response of a semi-infinite medium to a swift point charge moving parallel to its surface has been analysed theoretically. The aim has been to provide estimates of stopping power, straggling and lateral deflection of swift ions under grazing incidence on insulating and/or conducting targets. As a byproduct, similar estimates are obtained for swift ions moving parallel to a thin planar layer which may be helpful in the analysis of planar channeling at surfaces and in the bulk. The theoretical scheme is based on classical and quantal stopping theory in the impact parameter representation. Symmetry properties have been established relating the behavior above the surface plane to the behavior underneath. Well-established results from dispersion theory in the long-wavelength limit are reproduced. Those results do not apply to close collisions and become invalid near the surface. Corrections are applied ensuring a correct transition to bulk behavior. The effect of excited core electrons which has frequently been neglected is shown to be significant.
|Tidsskrift||Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms|
|Status||Udgivet - apr. 1997|