A MOLECULAR-DYNAMICS SIMULATION OF LIQUID BENZENE ADSORBED ON GRAPHITE

We study the physisorption of benzene on the basal plane of graphite in the high-temperature fluid phase using the molecular dynamics simulation technique. Intra-adsorbate interactions are modeled using the AMBER potential, whereas the adsorbate-substrate interactions are described via Steele's method in terms of a static external potential acting on the adsorbate. The simulations are carried out for temperatures between 150 and 300 K in the coverage range from 0.5 to 2.0. Our results provide insight into the surface induced structure within the fluid benzene film as a function of separation from the surface. In particular, we obtain results for the temperature and coverage dependence of the molecular position and orientation distribution perpendicular to the substrate. We find that at double layer coverage, the outer benzene layer exhibits structural behavior similar to the bulk fluid. In addition, we calculate the in-plane diffusion coefficient for mono- and submono-layer coverages at various temperatures.