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

The use of density-based basis-set correction (DBBSC)
[J. Phys. Chem. Lett. 2019, 10, 2931]
is extended to double-hybrid (DH) functionals. The proposed DBBSC-DH
approach significantly reduces the basis-set requirements for accurate
calculations, enabling near-basis-set-limit results using affordable
one-electron basis sets. The accuracy of this method is comparable
to that of the recently proposed DH functionals utilizing explicitly
correlated (F12) second-order perturbation theory contribution [J. Phys. Chem. Lett. 2022, 13, 9332];
however, its computational costs and resource demands are only a fraction
of those associated with the DH-F12 scheme. Applications to real-life
examples reveal that only a 30% overhead in wall-clock time is observed
compared to conventional DH calculations, demonstrating that the DBBSC-DH
approach is a compelling alternative to the excellent but relatively
costly DH-F12 functionals, particularly for extended molecular systems.