Near-Basis-Set-Limit Double-Hybrid DFT Energies with Exceptionally Low Computational Costs

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Accurate quantum chemical calculations often require large basis sets, increasing computational cost.
• Double-hybrid (DH) functionals offer improved accuracy but can be computationally demanding.
• Density-Based Basis-Set Correction (DBBSC) has previously reduced basis set requirements for some methods.

Purpose of the Study:

• To extend the Density-Based Basis-Set Correction (DBBSC) methodology to double-hybrid (DH) functionals.
• To assess the accuracy and computational efficiency of the new DBBSC-DH approach.
• To provide a cost-effective alternative to explicitly correlated (F12) DH functionals.

Main Methods:

• Implementation of DBBSC for double-hybrid density functional theory calculations.
• Comparison of DBBSC-DH results with conventional DH and DH-F12 methods.
• Evaluation of computational overhead and resource demands for DBBSC-DH.

Main Results:

• The DBBSC-DH approach enables near basis-set limit accuracy with affordable one-electron basis sets.
• Accuracy of DBBSC-DH is comparable to more expensive DH-F12 methods.
• DBBSC-DH exhibits only a ~30% wall-clock time overhead compared to standard DH calculations.

Conclusions:

• DBBSC-DH significantly reduces basis set requirements for accurate double-hybrid calculations.
• This method presents a computationally efficient and accurate alternative to DH-F12 functionals.
• DBBSC-DH is particularly advantageous for calculations involving extended molecular systems.