The hopping self diffusion coefficient of an adatom on the (100), (110) and (111) surfaces of nine FCC metals were investigated using Monte Carlo variational transition state theory and Lennard-Jones interactions. The metals that were studied were Ag, Al, Au, Cu, Ir, Ni, Pd, Pt and Rh. The potential parameters for the Lennard-Jones interactions were determined from the known experimental values of cohesive energies and lattice constants. The ratios, R, of the cohesive energy to the activation energy for diffusive hopping on the (111) and (100) surfaces were found to be 30 and 6, respectively. For diffusive hopping on the (110) surface, R depended upon the diffusion direction: R was 5 and 2.8 along the [110] and [001] directions, respectively. The pre-exponential factor, D0, for these metals was found to vary within a factor of three from the corresponding average value, (D0av for a given surface and diffusion channel). The pre-exponential factors corresponding to diffusion on the (111), (100), (110)[1¯10] and (110)[001] surfaces were found to satisfy an empirical expression in terms of R, lattice constant and the distance between the two nearest binding sites.

Predicting Trends in Rate Parameters for Self-Diffusion on FCC Metal Surfaces. P.M.Agrawal, B.M.Rice, D.L.Thompson: Surface Science, 2002, 515[1], 21-35