A generalized-gradient approximation exchange hole model for dispersion coefficients.

Area of Science:

• Computational chemistry
• Quantum chemistry
• Materials science

Background:

• Accurate calculation of dispersion coefficients is vital for modeling molecular interactions.
• Existing methods often face challenges with accuracy or computational cost.
• Density functional theory (DFT) commonly omits long-range van der Waals (vdW) interactions.

Purpose of the Study:

• To present a simple and accurate method for computing density-dependent dispersion coefficients.
• To develop a cost-effective variant suitable for large molecular systems.
• To enhance the accuracy of noncovalent interaction energy calculations in DFT.

Main Methods:

• Modeling dispersion coefficients using a generalized gradient-type approximation.
• Applying Becke and Johnson's exchange hole dipole moment formalism.
• Utilizing a disjoint description of atoms within molecules for a cost-effective variant.

Main Results:

• Achieved mean absolute errors below 10% for C(6) coefficients across 90 molecular complexes.
• Demonstrated a highly cost-effective variant of the method.
• Showcased accurate noncovalent interaction energies when incorporating pairwise corrections.

Conclusions:

• The presented method offers a significant improvement in calculating dispersion coefficients.
• The developed approach effectively captures long-range vdW interactions, enhancing DFT accuracy.
• This method provides a valuable tool for accurate computational studies of molecular systems.