A study was made of systematically the dimer diffusion on a series of metal face-centered cubic (001) surfaces. The atomic interactions were modelled by the realistic model potentials including embedded-atom method potential, surface-embedded-atom method potential, and Rosato-Guillopé-Legrand potential. Based on the results of the static calculations and the molecular dynamics simulations, three different kinds of face-centered cubic (001) surfaces could be distinguished named hard, middle, and soft. On the different kind of surfaces, not only the dominant diffusion mechanism but also the physical model for exchange mechanism was different. In addition, besides the conventional hopping and exchange mechanisms, other interesting diffusion mechanisms for dimers were observed in the molecular dynamics simulations: such as, exchange rotation, cooperative hopping and cooperative exchange.

Systematic Study of Dimer Diffusion on Metal FCC(001) Surfaces. Liu, Q., Sun, Z., Ning, X., Li, Y., Liu, L., Zhuang J.: Surface Science, 2004, 554[1], 32