The migration of H and D on the (332) surface was studied by using laser-induced thermal desorption techniques (table 247). A new boundary method was used to measure diffusion, at saturation coverages, parallel and perpendicular to the step direction (table 248). Due to a compensation effect, the diffusion coefficients differed by a factor of less than 2 at temperatures ranging from 150 to 250K. The activation energies were slightly higher than those which had previously been reported for the (111) surface. The results could be rationalized by assuming that a small additional energy barrier was associated with the steps (Schwoebel effect), and that kink sites also perhaps exerted some influence.

G.Hoogers, B.Lesiák-Orlowska, D.A.King: Surface Science, 1995, 327, 47-52

Table 247

Diffusivities of D and H on the (332) Surface of Rh