A MOLECULAR-DYNAMICS SIMULATION OF SMALL BENZENE CLUSTERS

Molecular dynamics calculations have been undertaken on small benzene clusters containing between two and six molecules, with each molecule being treated as a rigid rotor. As a function of kinetic temperature, calculated dynamic quantities associated with the translational and rotational motion of individual molecules, show that the clusters exhibit distinct solidlike and liquidlike forms. In all cases, the transition to a liquidlike state occurs at a temperature approximately 170 K below the melting point for bulk benzene. Melting in the tetramer is complicated by the presence of a metastable planer configuration to which the more stable tetrahedral arrangement is observed to isomerize. Power spectra, derived from angular velocity correlation functions, show that melting in the clusters is accompanied by an increase in motion about the C6 molecular axis. In contrast, motions about the C2 axes remain hindered even in the liquidlike clusters.