Highly anomalous values for the pre-exponential factor in atomic diffusion rates at surfaces were deduced from scanning-tunneling microscopy growth experiments. Using an extensive first-principles kinetic Monte Carlo study, it was shown here how long-range adsorbate interactions invalidated the standard nucleation-theory approach to analyzing experimental island-density data. When adatom-adatom interactions were properly accounted for in the analysis of experimental data, the anomaly was removed and the deduced pre-factors became consistent with direct theoretical calculations. It was shown that the dependence of the island density upon the growth rate was modified by interactions which could be used to identify adsorbate interactions in growth experiments.

Neglected Adsorbate Interactions behind Diffusion Prefactor Anomalies on Metals. S.Ovesson, A.Bogicevic, G.Wahnström, B.I.Lundqvist: Physical Review B, 2001, 64[12], 125423