The diffusive motion of 0.8 of a monolayer of methane, adsorbed on (100) surfaces, was measured at 72, 88 and 97K by using quasi-elastic neutron scattering. The corresponding translational diffusion coefficients were equal to about 5 x 10-6cm2/s at 88K and 1.2 x 10-5 cm2/s at 97K.

M.Bienfait, J.P.Coulomb, J.P.Palmari: Surface Science, 1987, 182[3], 557-66