Evaluating London Dispersion Interactions in DFT: A Nonlocal Anisotropic Buckingham-Hirshfeld Model

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Density Functional Theory (DFT) often requires corrections for van der Waals (vdW) interactions.
• Accurate description of dispersion forces is crucial for understanding molecular interactions.

Purpose of the Study:

• Introduce the novel BH-DFT-D model for evaluating London dispersion.
• Enhance the performance of local DFT exchange-correlation functionals for vdW interactions.

Main Methods:

• The BH-DFT-D model combines Buckingham's equations with Hirshfeld's distributed multipole analysis.
• It yields nonlocal, fully anisotropic expressions for dispersion interactions.
• The model is currently suitable for dimers with minimal or no overlap.

Main Results:

• The BH-DFT-D model was tested on various van der Waals dimers.
• It achieved a mean average error (MAE) of 0.20 kcal/mol compared to high-level data.
• Reproduced interaction energies at the BH-B3LYP-D/aug-cc-pVTZ level.

Conclusions:

• The BH-DFT-D model provides a promising approach for accurate dispersion energy calculations.
• Future developments include adding damping functions, analytical gradients, and generalizing to supramolecular systems.