Molecular-dynamics study of the diffusion coefficient on a crystal surface

We use molecular-dynamics simulation to study the migration of an individua l atom on the surface (010) of a (12-6) Lennard-Jones bcc crystal. Although the Lennard-Jones potential does not describe quantitatively all crystalli ne features, it can give us several clues on its thermodynamical behavior. We calculate the displacement self-correlation function and the residence t ime for a particle deposited on the crystal surface. We show that an anomal y occurs on these quantities which can be a signature of a premelting proce ss.