ANISOTROPY OF TRANSLATIONAL DIFFUSION IN PREMELTED METHANE FILMS

Surface melting of the (111) face of methane films adsorbed on graphit e is investigated by quasielastic neutron scattering with special atte ntion paid to translational diffusion within the liquid-like layer par allel and normal to the surface. The comparison of the experimental sp ectra measured in different geometries clearly shows diffusion anisotr opy. Simulations of the data provide an estimation of the anisotropy a s a function of temperature.