The diffusion of small Pd clusters on MgO(100) was theoretically investigated. It was found that small clusters could diffuse even faster than isolated adatoms by a variety of mechanisms (some of which were novel), such as dimer rotation, trimer walking, tetramer rolling, and sliding. The consequences of the diffusion of small clusters on the growth of Pd aggregates on MgO(100) were investigated, and it was shown that fast mobility of clusters larger than a single atom was essential to bring the theoretical results into agreement with the outcome of molecular beam epitaxy experiments.

Diffusion of Palladium Clusters on Magnesium Oxide. G.Barcaro, A.Fortunelli, F.Nita, R.Ferrando: Physical Review Letters, 2005, 95[24], 246103 (3pp)