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

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Intermolecular Forces

Background:

• The Quantum Drude Oscillator (QDO) model is a key tool for calculating van der Waals (vdW) interactions.
• Anisotropic QDO models have advanced by considering molecular fragments instead of single atoms.
• Existing QDO models require improvements in fragmentation methods and dispersion corrections for enhanced accuracy.

Purpose of the Study:

• To evaluate the effectiveness of dipole-dipole interactions within an anisotropic QDO framework without employing fragmentation.
• To introduce a novel anisotropic damping function tailored for anisotropic QDO models.
• To assess the predictive power of the revised model for vdW complex binding energies.

Main Methods:

• Implementation of an anisotropic QDO model.
• Inclusion of dipole-dipole interactions without fragmentation.
• Development and application of a new anisotropic damping function.
• Calculation of binding energies for various vdW complexes.

Main Results:

• The revised anisotropic QDO model demonstrates accurate prediction of vdW binding energies for most tested systems.
• The model successfully incorporates dipole-dipole interactions and anisotropic damping.
• The study highlights the limitations of the dipole approximation in anisotropic QDO modeling.

Conclusions:

• The developed anisotropic QDO model offers a robust method for calculating vdW interactions, particularly for complexes where fragmentation is challenging.
• The integration of dipole-dipole interactions and anisotropic damping significantly improves accuracy.
• This research underscores the importance of considering the nuances of dipole approximations in advanced quantum mechanical models.