Universal Pairwise Interatomic van der Waals Potentials Based on Quantum Drude Oscillators

Repulsive short-range and attractive long-range van der Waals (vdW) forces play an appreciable role in the behavior of extended molecular systems. When using empirical force fields, the most popular computational methods applied to such systems, vdW forces are typically described by Lennard-Jones-like potentials, which unfortunately have a limited predictive power. Here, we present a universal parameterization of a quantum-mechanical vdW potential, which requires only two free-atom properties-the static dipole polarizability alpha(1) and the dipole-dipole C-6 dispersion coefficient. This is achieved by deriving the functional form of the potential from the quantum Drude oscillator (QDO) model, employing scaling laws for the equilibrium distance and the binding energy, and applying the microscopic law of corresponding states. The vdW-QDO potential is shown to be accurate for vdW binding energy curves, as demonstrated by comparing to the ab initio binding curves of 21 noble-gas dimers. The functional form of the vdW-QDO potential has the correct asymptotic behavior at both zero and infinite distances. In addition, it is shown that the damped vdW-QDO potential can accurately describe vdW interactions in dimers consisting of group II elements. Finally, we demonstrate the applicability of the atom-in-molecule vdW-QDO model for predicting accurate dispersion energies for molecular systems. The present work makes an important step toward constructing universal vdW potentials, which could benefit (bio)molecular computational studies.

Automated summary

This study presents a universal parameterization method for quantum-mechanical van der Waals (vdW) potentials based on two free-atom properties, namely the static dipole polarizability and the dipole-dipole C-6 dispersion coefficient. The derived vdW-QDO potential accurately predicts vdW binding energy curves for noble-gas dimers and exhibits correct asymptotic behavior. It is also shown to accurately describe vdW interactions in dimers consisting of group II elements. The applicability of the atom-in-molecule vdW-QDO model for predicting dispersion energies for molecular systems is demonstrated. This work is an important step toward constructing universal vdW potentials for (bio)molecular computational studies.