The migration of H on the (100) surface was studied by linearly diffracting a laser beam probe from a monolayer grating of adsorbed H. It was found that, at temperatures of between 110 and 161K, the Arrhenius plot revealed a marked levelling-off of the diffusion coefficient at about 144K (table 17). This deviation was attributed to the appearance of quantum diffusion. It was suggested that the underlying surface diffusion was governed by an activation energy of 3.5kcal/mol.

X.D.Zhu, A.Lee, A.Wong, U.Linke: Physical Review Letters, 1992, 68[12], 1862-5

Table 17

Diffusivity of H on (100) Plane of Ni