A double-hybrid density functional based on good local physics with outstanding performance on the GMTKN55 database

TL;DR

This paper introduces DH23, a new 12-parameter double-hybrid density functional that incorporates second-order perturbation terms, achieving the lowest error on the GMTKN55 database to date.

Contribution

The paper presents a novel double-hybrid density functional with 12 parameters, incorporating second-order perturbation theory, and demonstrates its outstanding performance on the GMTKN55 database.

Findings

Lowest GMTKN55 WTMAD2 error for a double-hybrid functional

Inclusion of second-order perturbation terms improves accuracy

Outperforms previous density functionals on benchmark tests

Abstract

In two recent papers [A. D. Becke, J. Chem. Phys. 156, 214101 (2022) and 157, 234102 (2022)] we compared two Kohn-Sham density functionals based on physical modelling and theory with the best density-functional power-series fits in the literature. The best error statistics reported to date for a hybrid functional on the GMTKN55 chemical database of Goerigk, Grimme, and coworkers [Phys. Chem. Chem. Phys. 19, 32184 (2017)] were obtained. In the present work, additional second-order perturbation-theory terms are considered. The result is a 12-parameter double-hybrid (DH) density functional with the lowest GMTKN55 "WTMAD2" error yet seen for a DH functional. We call it "DH23".