Dynamics of intermediate-length alkane films absorbed on graphite

The dynamics of flexible chain molecules near a solid interface is of funda mental interest in polymer science. This paper makes a preliminary report o n a quasielastic neutron scattering study of the dynamics of monolayer film s of C24H50 adsorbed on graphite. Quasielastic scattering was observed at t emperatures as low as similar to 180 K, well below the monolayer melting te mperature of 340 K, Preliminary analysis of the data indicates that at 230 K the entire molecule executes a rolling motion about its long axis while t he terminal methyl groups exhibit relatively rapid reorientation.