Methane dynamics in the 36 Å mesopores of MCM-41 studied by neutron scattering

The capillary melting of methane adsorbed into the uniform parallel mesopores of the new silicate MCM-41 has been studied by neutron inelastic scattering and neutron quasielastic scattering at an energy resolution of about 80 microelectron volts. Differences from bulk methane in both the rotational melting and the solid to liquid transition have been identified. Rotational melting occurs at about 35 K, nearly ten degrees above the onset for the bulk; translational melting starts at around 60 K, nearly 30 degrees below the melting point of bulk methane.