Neutron-Scattering Studies of the Structure and Dynamics ofAr36Monolayer Films Adsorbed on Basal-Plane-Oriented Graphite

Elastic- and inelastic-neutron-scattering methods have been used to study the low-temperature properties of argon films adsorbed on graphite. At $T=5\mathrm{}$ K the film forms a two-dimensional triangular lattice incommensurate with the substrate. The spectrum of neutrons inelastically scattered in the plane of the film is found to be consistent with calculations based on a simple two-dimensional phonon model in which interactions with the substrate are neglected.