Minimizing density functional failures for non-covalent interactions beyond van der Waals complexes.

Area of Science:

• Computational chemistry
• Quantum mechanics
• Materials science

Background:

• Kohn-Sham density functional theory (KS-DFT) is widely used for electronic structure calculations.
• Semilocal approximations in KS-DFT struggle to accurately describe dispersion interactions, especially at longer distances.
• Accurate modeling of weak interactions is essential for understanding molecular behavior and material properties.

Purpose of the Study:

• To develop and implement improved dispersion corrections for KS-DFT.
• To enhance the accuracy of inter- and intramolecular interaction energy calculations.
• To provide guidance for future development of density functional approximations.

Main Methods:

• Development of empirical and density-dependent dispersion corrections, including dD10 and dDsC.
• Modification of the Tang and Toennies damping function and derivation of accurate dispersion coefficients.
• Validation through reaction energies, geometries, molecular dynamics, and comparison with self-consistent methods.

Main Results:

• Dispersion corrections, particularly dDsC, significantly improve interaction energy calculations for various density functionals.
• The dDsC scheme demonstrates broad applicability and robustness across different molecular systems and interactions.
• Analysis reveals the interplay between delocalization error and missing dispersion in standard functionals.

Conclusions:

• The developed dispersion correction schemes substantially reduce errors in KS-DFT calculations.
• Accurate description of dispersion interactions is crucial for reliable predictions in chemistry and materials science.
• The study offers insights into functional development and the selection of appropriate density functionals for specific applications.