Molecular dynamics simulations were used to study the migration of an individual atom on the (010) surface of a 12-6 Lennard-Jones body-centered cubic crystal. Although the Lennard-Jones potential did not quantitatively describe all of the crystal features, it could furnish clues as to its thermodynamic behavior. The displacement self-correlation function, and the residence time for a particle deposited onto the crystal surface, were calculated. It was shown that an anomaly occurred in these quantities, and this was suggested to reflect the occurrence of a pre-melting process. The migration of an adatom could occur via 2 mechanisms. At low temperatures, the adsorbed particle could move through channels on the surface because the thermal motion of surface atoms had a low amplitude. As the temperature increased, the surface began to melt, the channels closed, and adatoms were stuck in the vicinity of a surface atom. This situation persisted until the adatom was thermally activated, and random-walk diffusion occurred. The underlying reason for this regime seemed to be the open structure of the body-centered cubic (010) surface.

Molecular Dynamics Study of the Diffusion Coefficient on a Crystal Surface. F.J.Resende, B.V.Costa: Physical Review B, 2000, 61[19], 12697-700