A MONTE-CARLO STUDY OF THE CONDENSED PHASES OF BIPHENYL

Detailed calculations on the condensed phases of biphenyl have been ca rried out by the variable shape isothermal-isobaric ensemble Monte Car lo method. The study employs the Williams and the Kitaigorodskii inter molecular potentials with several intramolecular potentials available from the literature. Thermodynamic and structural properties including the dihedral angle distributions for the solid phase at 300 K and 110 K are reported, in addition to those in the liquid phase. In order to get the correct structure it is necessary to carry out calculations i n the isothermal-isobaric ensemble. Overall, the Williams model for th e intermolecular potential and Williams and Haigh model for the intram olecular potential yield the most satisfactory results. In contrast to the results reported recently by Baranyai and Welberry, the dihedral angle distribution in the solid state is monomodal or weakly bimodal. There are interesting correlations between the molecular planarity, th e density and the intermolecular interaction.