Formation and cascading decay of hollow Ar atoms at a Si surface

Theoretical work was performed to investigate the formation and cascading d ecay of hollow Ar atoms during the interaction near a surface of Si. To exh ibit the static aspect of hollow atom formation below the surface, the dens ity functional theory was applied to evaluate results for electron charge d ensity plots of atomic orbitals. To study the dynamic properties of hollow Ar atoms, a complex cascade model was developed treating the successive fil ling of the K, L, and M shells via Auger transitions and collisional charge transfer above the surface and in the bulk. Information is provided for th e above- and below-surface contributions in previous experiments of Ar17+ i mpact on SiH using high-resolution x-ray spectroscopy. Clear evidence is gi ven that the velocity-dependent filling of the M shell plays a significant role. (C) 1999 Elsevier Science B.V.