Atomic behavior at individual binding sites: Ir, Re, and W on Ir(111).
It has for the first time become possible to make quantitative determinations of differences in energy and jump rate for adatoms at the two types of binding sites on a close-packed fcc (111) plane. For iridium on Ir(111), variations in the potential energy of an atom over the surface are found to be small. Binding energies are, however, strongly dependent upon the chemical identity of the adatom. For rhenium and tungsten, differences in binding at fcc and hcp sites are sizable. In contrast, the dynamics of jumps out of the two types of sites are similar for the same atom.