LENNARD-JONES POTENTIAL MODEL FOR THE CONDENSED PHASES OF C-70

A simplified site-site Lennard-Jones (LJ) model for the intermolecular potential of C-70 is studied by a series of classical constant-pressu re molecular-dynamics calculations of C-70 crystals, at several temper atures and zero pressure. The molecular model approximately,simulates the real molecular volume and form and consists of 12 LJ interaction s ites arranged in a polyhedra of D-5h symmetry. It is found that this s imple model reproduces many properties of cubic and hexagonal crystals of C-70, although further improvement is needed, mainly in the temper atures of the succesive phase transitions.