Optimization of effective atom centered potentials for london dispersion forces in density functional theory

Area of Science:

• Computational chemistry
• Quantum mechanics

Background:

• Standard density functional theory (DFT) methods often fail to accurately describe systems with significant London dispersion forces.
• Accurate modeling of van der Waals interactions is crucial for predicting molecular properties and complex formation.

Purpose of the Study:

• To introduce and validate an effective atom-centered nonlocal term for DFT.
• To improve the description of London dispersion forces in generalized gradient approximation (GGA) DFT calculations.
• To enable accurate prediction of equilibrium geometries and dissociation energies for molecular complexes.

Main Methods:

• Incorporation of an effective atom-centered nonlocal term into the exchange-correlation potential.
• Calibration of the long-range correction using density functional perturbation theory.
• Application of the corrected GGA-DFT to various molecular complexes, including van der Waals systems.

Main Results:

• The corrected DFT approach successfully captures London dispersion forces.
• Accurate equilibrium geometries were obtained for argon-argon, benzene-benzene, graphite-graphite, and argon-benzene complexes.
• Accurate dissociation energies were predicted for these complexes without prior knowledge of fragment types or structures.

Conclusions:

• The developed nonlocal correction effectively addresses the deficiency of standard DFT regarding dispersion forces.
• This method provides a reliable and generalizable approach for studying van der Waals interactions in molecular systems.
• The approach offers accurate predictions for complex geometries and energies, enhancing computational chemistry capabilities.