A Comparative Study for Molecular Dynamics Simulations of Liquid Benzene.

The classical equilibrium and nonequilibrium molecular dynamics simulations for liquid benzene, the prototypical aromatic π-π interaction system, are performed using a variety of molecular force fields, OPT-FF, AMBER 03, general AMBER force field (GAFF), OPLS-AA, OPLS-CS, CHARMM27, GROMOS 53A5, and GROMOS 53A6. The simulated results of the molecular structure and thermodynamic properties of liquid benzene are compared with the experimental data available in the literature, accounting for the superiority of each force field in the descriptions of the π-π interaction system. The OPLS-AA force field is recommended to be the best one, which reproduces quite well the properties examined in this work, while the others fail in predicting either the local structure or the thermodynamic properties. Such distinct discrepancies for the above force fields are discussed within the scheme of the pairwise interaction construction of the standard force field, which will stimulate searching for a force field with generally good quality not only in terms of microstructure descriptions but also in the predictions of the thermodynamic properties of the liquids.