Clusters and layers ofC60molecules supported on a graphite substrate

Using the models proposed by Girifalco and by Ruoff and Hickman for describing the ${\mathrm{C}}_{60}$-${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{60}$-graphite interactions, respectively, we have carried out a computer simulation study of the structures and phase changes of clusters of ${\mathrm{C}}_{60}$ molecules supported on a graphite substrate. We have also analyzed the configurations and binding energies of layers of ${\mathrm{C}}_{60}$ molecules deposited on the same substrate. It is predicted that the ground-state structures of the supported clusters consist in monolayerlike hexagonal arrangements parallel to the graphite surface, and that when the temperature is raised the supported fullerene clusters lose ${\mathrm{C}}_{60}$ molecules by sublimation before they can attain a liquidlike state.