The non-equilibrium diffusion of highly hyperthermal atoms resulting from dissociative adsorption of a diatomic molecule was investigated using molecular dynamics and an effective-medium model potential. The parameters of the potential were chosen to describe O2 on Al(111) and the simulation results were considered with regard to previous scanning tunnelling microscopic measurements for this system. The transient displacement along the surface was found to be about one order of magnitude larger than the distance to the nearest adsorption site. The travelling distance was limited mainly by the rapid randomization of the adsorbate motion, and not primarily by the rate of energy transfer to the substrate degrees of freedom.

Transient Hyperthermal Diffusion Following Dissociative Chemisorption: a Molecular Dynamics Study. Engdahl, C., Wahnström, G.: Surface Science, 1994, 312[3], 429-40