A simple fragment-based method for van der Waals corrections over density functional theory

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Molecular Modeling

Background:

• Accurate modeling of intermolecular noncovalent interactions in large molecules is computationally expensive.
• Fragment-based methods reduce computational cost but may not fully capture electron density fluctuations.
• Atom-centered quantum Drude oscillators effectively model interactions from electron density fluctuations.

Purpose of the Study:

• To develop a cost-effective method for describing intermolecular van der Waals interactions.
• To amalgamate Drude oscillator modeling with molecular fragmentation for improved accuracy.
• To reduce empirical parameters in interaction energy calculations.

Main Methods:

• Developed a novel method combining Drude oscillators with molecular fragmentation.
• Applied the method to calculate intermolecular van der Waals interactions.
• Used interaction energies as corrections to the PBE density functional theory (DFT) functional.
• Tested the method on the S66X8 benchmark database.

Main Results:

• The developed method achieved significant success on the S66X8 database.
• The method demonstrates accuracy on par with Grimme's DFT-D3 method.
• The approach successfully employs anisotropic oscillators for modeling electron fluctuation.
• Reduced the number of empirical parameters compared to traditional DFT-D methods.

Conclusions:

• The amalgamation of Drude oscillators and molecular fragmentation provides an accurate and efficient way to model van der Waals interactions.
• This proof-of-concept study demonstrates the potential of anisotropic oscillators in electron fluctuation modeling.
• The new method achieves high accuracy with fewer parameters, offering a competitive alternative to existing dispersion correction methods.