Abstract:

A novel DFT-D method, B972-PFD, has been found by combining the B972 hybrid density functional with the empirical dispersion correction based on the spherical atom model (SAM). The performance of the B972-PFD method is assessed on the S66, S66x8, and S22 standard data sets, atmospheric hydrogen-bonded clusters, the Adenine-Thymine π…π stacked, Watson-Crick hydrogen-bonded complexes, and the methane to (H₂O)₂₀ water cluster. The benchmark results of the S66 test set show that B972-PFD and three recently developed density functionals, ωB97X-V, B97M-V, and ωB97M-V developed by the Head-Gordon group, are at the same level of accuracy, and have an root-mean-square deviation (RMSD) of binding energies less than 1 kJ·mol^-1 relative to the CCSD(T)/CBS gold standard. The B972-PFD method also showed excellent accuracy in other data set tests. The basis set effect of the B972-PFD method has been benchmarked, and we recommend that the favorable price/performance ratios basis set is Pople's 6-311++G(2d, p).

Key words: Intermolecular Interaction, DFT-D, Spherical atom model for dispersion correction, B972-PFD