A simulation of diffusion of Au on Au(111) and of Ag on Ag(111) was performed over a wide range of temperatures, up to about one half of the melting temperature of the crystals. Au and Ag were modelled using many-body potentials derived within the second-moment approximation to the tight-binding model. The potential energy barriers (zero temperature) for diffusion were calculated by allowing a full relaxation of the crystal; those barriers result rather low in both metals and especially in Ag. However, in the temperature range considered, the activation energies, as extracted from the Arrhenius plots of the diffusion coefficient, were not significantly different from the potential energy barriers at 0K.

Tight-Binding Molecular Dynamics Study of Diffusion on Au and Ag(111). Ferrando, R., Tréglia, G.: Surface Science, 1995, 331-333[B], 920-4

Table 2

Simulated diffusion coefficients for Ag and Au