Comparative Study of Force Fields for Benzene

Abstract

We have examined the ability of several atomic force fields of different forms to reproduce the structure and binding energy of benzene dimer as determined from quantum chemistry calculations, the experimental gas-phase second virial coefficient of benzene, and thermodynamic and structural properties of liquid benzene. The force fields investigated were a united atom Lennard-Jones potential, a united atom Lennard-Jones potential with a point quadrupole, an anisotropic united atom model, and explicit (all) atom force fields with partial atomic charges and without partial atomic charges. These force fields which do not include electrostatic interactions predicted the planar sandwich structure (D6h) to be the most stable dimer structure, in contrast to quantum chemistry calculations that indicate that the planar sandwich structure is a saddle point between stable parallel displaced (C2h) geometries. Only the explicit atom + partial charge model predicted benzene dimer structures and energies that are in qual...