Thin Methane Film Growing Mode on MgO/100 Surface

Results of neutron diffraction study and volumetric adsorption measurements are presented for thin methane films adsorbed on a highly homogeneous MgO powder surface. A layer-by-layer growing mode from a square (100) interface is observed up to a four-layer film thickness at 77 K. In that regime, the CH4 film is commensurate C(2, 2) with the (100) MgO surface. At higher coverage, observation of bulk methane crystallites indicates that the growing mode is probably of the Stranski-Krastanov type.