Adsorption ofCCl4on graphite

We have performed a comprehensive x-ray scattering study of ${\mathrm{CCl}}_4$ adsorbed on exfoliated graphite. We observe the following features. At low coverages, there is an incommensurate triangular monolayer solid, with a gas-liquid-solid triple point at 195 K. Below a temperature of 215 K the graphite is partially wet by only one monolayer. The monolayer solid has a maximum melting temperature of ∼246 K. A two-layer solid phase, which melts at 236 K, does not have a simple triangular structure. There is a liquid prewetting film of at least ten layers thickness at 246 K, 4 K below the bulk ${\mathrm{CCl}}_4$ triple point.