Comprehensive Benchmarking of a Density-Dependent Dispersion Correction.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Standard density functional approximations struggle with nonoverlapping electron densities.
• Accurate modeling of intermolecular and intramolecular interactions is crucial in chemistry.

Purpose of the Study:

• To introduce a density-dependent energy correction (dDsC) to improve density functional theory calculations.
• To enhance the accuracy of describing van der Waals interactions and charge-overlap effects.

Main Methods:

• Developed dDsC based on dispersion coefficients from generalized gradient approximation and an extended Tang-Toennies damping function.
• Computed dispersion coefficients using Becke and Johnson's exchange-hole dipole moment formalism.
• Validated the method on 341 reaction energies across 18 test sets.

Main Results:

• The B97-dDsC functional achieved a mean absolute deviation (MAD) of 1.3 kcal mol(-1) for reaction energies.
• dDsC demonstrated robust performance and general accuracy for diverse intra- and intermolecular interactions.
• Outperformed M06-2X and B2PLYP-D3 with lower computational cost.

Conclusions:

• The dDsC approach offers a significant improvement over standard approximations for electronic structure calculations.
• Its density-dependent nature makes it particularly valuable for modeling redox reactions and charged species.
• Provides a computationally efficient and accurate method for quantum chemical simulations.