Molecular dynamics simulation results on the structural and diffusive properties of small (3 to 7 atoms) 2-dimensional Au clusters on Cu (111) surfaces were considered. It was found that the clusters were expanded in the direction normal to the surface, while the surface layer was contracted; depending upon the cluster size. These relaxations exhibited a power-law temperature dependence. The mean-square displacements of both cluster and

 surface atoms increased linearly with temperature, while a size dependence was found in the case of cluster atoms. A trajectory analysis revealed many cluster diffusion processes; among them concerted motion events, in agreement with available theoretical and experimental data. However, it appeared that the diffusion took place mainly via mechanisms which involved a rapid succession of sub-processes, each implicating a few cluster atoms. The overall atomic and cluster diffusion coefficients were calculated and it was found that they exhibited an Arrhenius behavior; from which the corresponding activation energies were deduced.

Structural and Diffusive Properties of Small 2D Au Clusters on the Cu (111) Surface. V.Papathanakos, G.A.Evangelakis: Surface Science, 2002, 499[2-3], 229-43