Results of step fluctuation experiments for Mo(011), using low-energy electron microscopy, were re-examined using procedures that offered accurate coefficients of surface mass diffusion. By this means, the surface diffusion was found at homologous temperatures of about 0.5, while a cross-over to relaxation driven by bulk vacancy diffusion was deduced to occur at homologous temperatures of about 0.6 (for Tm = 2896K). The relationship,

D (cm2/s) = 4 x 10-4 exp[-1.13(eV)/kT]

was obeyed at 1080 to 1680K. Possible indications of diffusion along step edges appeared at homologous temperatures of about 0.4.

M.Ondrejcek, W.Swiech, C.P.Flynn: Surface Science, 2006, 600[20], 4673-8