Binding Energies of Transition-Metal Atoms Adsorbed on a Transition Metal

The binding energies of transition-metal atoms of the $5d$ series adsorbed on a $5d$ transition metal are calculated in the tight-binding approximation. The general features of the variation of the binding energy with the number of adatom $5d$ electrons are similar for all the substrates. It shows a parabolic behavior with a maximum of the order of the cohesive energy for the substrate, and a subsequent sharper decrease as the number of adatom $5d$ electrons is increased. The maximum is always located close to tungsten, as in the case of a tungsten substrate, where it is between tungsten and rhenium.