The diffusion of individual Pt atoms on the (001) surface were investigated by means of field ion microscopy. The pattern of binding sites which was traced out by an atom as it diffused across the surface, at 170 to 205K, indicated that individual displacements occurred only in the [100] and [010] directions. Migration in these directions was consistent with the operation of an atomic exchange mechanism. No evidence for diffusion via ordinary hopping was found within the present temperature range. The data could be described by:

D (cm2/s) = 0.0013 exp[-0.47(eV)/kT]

Diffusion off the plane edge was not observed at temperatures below 215K.

G.L.Kellogg: Surface Science, 1991, 246, 31-6