Modeling coarse-grained van der Waals interactions using dipole-coupled anisotropic quantum Drude oscillators

The Quantum Drude Oscillator (QDO) model is a promising candidate for accurately calculating the van der Waals (vdW) energies. Anisotropic QDO models have recently been used to represent molecular fragments rather than single atoms. While this model promises accurate calculation of vdW energies, there is significant room for improvements such as incorporating a proper fragmentation method, higher-order dispersion corrections, etc. The present work attempts to gauge dipole-dipole interactions’ ability without fragmentation. A suitable anisotropic damping function is also introduced to work with anisotropic QDO. This revised model accurately predicts the vdW complex for the majority of the systems considered. This work indicates the limit of dipole approximation for an anisotropic QDO-based model.