Molecular dynamics simulations were used to investigate atomic mobility and diffusivity in a generalized Frenkel-Kontorova model which took account of the anharmonic (exponential) interaction of atoms that were subjected to a 3-dimensional substrate potential that was periodic in 2 dimensions, and non-convex in the third dimension. The numerical results were explained in terms of a phenomenological theory which treated a system of strongly interacting atoms as a system of weakly interacting quasi-particles (kinks). The model parameters were chosen so as to be close to those for the K/W(112) adsorption system.

O.M.Braun, T.Dauxois, M.V.Paliy, M.Peyrard: Physical Review B, 1996, 54[1], 321-31