Both the formation energies and the intra- and inter-layer activation energies of self-diffusion of a single vacancy in the first five planes of Pd(111) surface were investigated by means of molecular dynamics in conjunction with the semi-empirical many-body potential of the modified analytical embedded-atom method. The results showed that the effect of the surface on the vacancy was only down to the fourth layer. It was easier for a single vacancy to form and to migrate in the first layer. Furthermore, the vacancy in the second layer was favorable to migrate to the first layer. This was in agreement with the experimental results that the first layer has the highest concentration of the vacancy.

Computer Simulation Study of Self-diffusion in Pd(111) Surface. G.X.Chen, J.M.Zhang, K.W.Xu, V.Ji: Journal of Molecular Catalysis A, 2006, 258[1-2], 341-5