By using a surface ionization microscope, the directional dependence of diffusion was measured on an O-covered (112) surface at extremely low K-coverages. It was found that the O coverage did not affect the diffusion anisotropy which was observed on clean surfaces, but had the effect of reducing the diffusion rate. Diffusion along channels on the surface could be described by:

D (cm2/s) = 9.0 x 10-1 exp[-0.60(eV)/kT]

whereas diffusion at 60º to the channels could be described by:

D (cm2/s) = 2.0 x 10-1 exp[-0.72(eV)/kT]

B.Bayat, H.W.Wassmuth: Physics Letters A, 1986, 115[5], 225-9

The best linear fits to the solute diffusion data ([5] to [25]) yield:

H (sd): Ln[Do] = 1.49E – 21 (R2 = 0.87); W(sd): Ln[Do] = 0.33E – 16.1 (R2 = 0.63)