Systematic Evaluation of Counterpoise Correction in Density Functional Theory

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Supramolecular Chemistry

Background:

• The Boys-Bernardi counterpoise (CP) correction is widely believed to overcorrect supramolecular interaction energies.
• This perceived overcorrection is often attributed to artifacts from low-quality basis sets in correlated wave function methods.

Purpose of the Study:

• To systematically assess the efficacy of the CP correction procedure in density functional theory (DFT).
• To evaluate CP correction for various DFT functionals and basis sets, including small dimers and large molecular complexes.

Main Methods:

• Systematic assessment of the CP correction procedure across representative DFT functionals and basis sets.
• Evaluation using benchmark datasets of small dimers and large supramolecular complexes (polymers and ligand-protein models).

Main Results:

• CP correction enables near-complete-basis quality interaction energies with inexpensive double-ζ basis sets.
• CP-corrected energies show reduced sensitivity to computationally expensive diffuse basis functions.
• Results challenge the notion that CP correction overcorrects for basis-set incompleteness.

Conclusions:

• CP correction is essential for accurate supramolecular interaction energies, especially with smaller basis sets.
• The CP procedure does not necessarily overcorrect; its effectiveness depends on basis set quality.
• This work provides a cost-effective pathway to high-accuracy calculations for large systems.