Interaction of Rydberg atoms with surfaces: Electron tunneling processes

The interaction of atomic Rydberg states with surfaces in the presence of an external electric field is being investigated with an ab initio theory to gain new insights into the behavior of atomic states near surfaces and to evaluate their use as an experimental probe of electron tunneling processes at surfaces. The present calculations reveal that as Rydberg atoms approach a clean metal surface strong hybridization occurs that depends on both the atom-surface separation and the applied electric field. The electron probability density for some hybridized states is maximal toward the surface, for others toward vacuum. The calculated tunneling rates (widths) are orders of magnitude larger for states oriented toward the surface. Also, theory is presented showing that electron tunneling rates can be changed significantly by the presence of a thin dielectric overlayer at the surface.