Field-ion microscopy was used to study surface self-diffusion on the (331) plane at 155 to 180K. The results could be described by:

D (cm2/s) = 2.3 x 10-3 exp[-10.3(kcal/mol)/RT]

R.T.Tung, W.R.Graham: Journal of Chemical Physics, 1978, 68[10], 4764-5