Dispersionless Nonhybrid Density Functional.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Density Functional Theory (DFT) is a powerful quantum mechanical modeling method.
• Accurate description of non-covalent interactions, particularly van der Waals forces, remains a challenge in DFT.
• Existing dispersion-corrected DFT (DFT+D) methods have limitations in accuracy and computational cost.

Purpose of the Study:

• To develop a novel, accurate, and efficient dispersion-corrected DFT (DFT+D) method.
• To optimize a new nonhybrid generalized gradient approximation (GGA) functional with a dispersion component.
• To evaluate the performance of the new method against established DFT+D approaches.

Main Methods:

• Development of a new dispersion-corrected DFT (DFT+D) method.
• Inclusion of a nonhybrid dispersionless GGA functional and a literature-parametrized dispersion function.
• Optimization of 9 adjustable parameters using a training set of 589 benchmark interaction energies.

Main Results:

• The new DFT+D method achieved a mean unsigned error of 0.33 kcal/mol for interaction energies.
• Outperformed other GGA-based DFT+D methods in accuracy.
• Demonstrated comparable or superior performance to more computationally expensive meta-GGA and hybrid DFT+D functionals.
• The dispersion energy component accurately reflects true dispersion energy across intermolecular separations.

Conclusions:

• The developed DFT+D method represents a significant advancement in computational chemistry for describing non-covalent interactions.
• Offers a balance of high accuracy and efficiency, making it suitable for various applications.
• Provides a more accurate representation of dispersion energies compared to existing DFT+D methods.