A calculation of the diffusion energies for adatoms on surfaces of F.C.C. metals

The activation energies for diffusion were determined for gold, platinum and iridium adatoms on (110) and (311) Pt surfaces and were found to be in good agreement with the measurements reported by Bassett and Webber. The Lennard-Jones pair potentials were used to model the interatomic forces, and relaxation of the substrate atoms in near proximity to the adatom was considered in detail. The present calculations clarify the mechanism of the observed two-dimensional diffusion of platinum and iridium atoms on a (110) Pt surface. The results are compared with those obtained using Morse potential functions and different relaxation techniques.