Evaluation of the Hartree−Fock Dispersion (HFD) Model as a Practical Tool for Probing Intermolecular Potentials of Small Aromatic Clusters: Comparison of the HFD and MP2 Intermolecular Potentials

Abstract

The performance of the Hartree−Fock dispersion (HFD) model for aromatic clusters has been evaluated by comparing the HFD/6-31G intermolecular potentials with the MP2/6-31G potentials for dimers of four aromatic hydrocarbons (benzene, naphthalene, anthracene, and pyrene) and the trimer of naphthalene. The computationally efficient HFD model yields equilibrium geometries and binding energies that are essentially identical to those from the MP2 calculations for all aromatic clusters. For the T-shaped dimer of benzene and the cyclic trimer of naphthalene for which experimental geometries are known, the computed geometry and intermolecular separations are in excellent agreement with the experimental data. Although the MP2/6-31G (not corrected for basis set superposition errors) and HFD/6-31G binding energies (De) of the dimers of benzene and naphthalene, and the trimer of naphthalene, are almost a factor of 2 greater than the experimental values (D0), they are considerably in better agreement with experiment t...