Measurements were performed by using a surface ionization ion microscope. It was found that the surface diffusion of K on a clean (112) surface was highly anisotropic. That is, diffusion along so-called channels in the [111]-type directions was appreciably faster than that in the perpendicular [110]-type directions. The data could be described by:

parallel:     D (cm2/s) = 3 x 10-1 exp[-0.46(eV)/kT]

perpendicular:     D (cm2/s) = 3 x 10-1 exp[-0.76(eV)/kT]

B.Bayat, H.W.Wassmuth: Surface Science, 1983, 133[1], 1-8

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)