Theory Concerning the Interaction of an Alkali Atom and a Metallic Surface

The interaction of a metallic surface with an alkali atom causes both a shift and a broadening of the valence level of the atom. We first present the theoretical model which describes the phenomenon and then calculate this shift and broadening by using a perturbation theory. The results are computed for the adsorption of cesium on tungsten and of lithium on rhenium.