Electron tunneling rates between an atom and a corrugated surface

An investigation of the lateral variations of the widths of atomic levels outside realistic surfaces is presented. The surfaces are modeled using finite clusters. The widths of the atomic levels are obtained by calculating the electronic structure of the atom/surface system and projecting the density of states upon the atomic levels. An investigation of cluster size dependence of the calculated widths is presented. It is shown that in the region near the surface, the widths are well converged already for relatively small clusters. An application to Li outside Al(001) and Si(110) surfaces shows that the lateral variation of the width of the Li(2s) level can be very significant.