Diffusion of a small two-dimensional symmetrical cluster Pd7 on the Pd(111) surface was studied using canonical ensemble molecular dynamics with a many-body potential derived from first-principles calculations in bulk Pd. The results of simulations performed at 800K revealed several cluster diffusion events. Such events occurred; generally preserving the symmetrical shape. Nevertheless, the simulations indicated that distortion events did occur in a short time interval. During this interval, more frequent diffusion events occurred, with subsequent re-composition of the original shape of the cluster. These intermediate distorted states were short-lived and would therefore probably not be seen in experiment. The migration mechanism was mainly row gliding for the compact symmetrical cluster while, for the distorted form, the predominant process was a combination of single atom moves and edge gliding.

Diffusion of Pd Clusters on Pd(111) Surfaces: a Molecular Dynamics Study. Da Silva, E.Z., Antonelli, A.: Surface Science, 2000, 452[1-3], 239-46