Dispersion-corrected r²SCAN based double-hybrid functionals

05 September 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


The regularized and restored semi-local meta-generalized gradient approximation (meta-GGA) exchange-correlation functional r²SCAN [J. W. Furness, A. D. Kaplan, J. Ning, J. P. Perdew, and J. Sun, J. Phys. Chem. Lett. 11, 8208–8215 (2020)] is used to create adiabatic-connection-derived global double-hybrid functionals employing spin-opposite-scaled MP2. The 0-DH, CIDH, QIDH, and 0-2 type double-hybrid functionals are assessed as a starting point for further modification. Variants with 50% and 69% Hartree--Fock exchange (HFX) are empirically optimized (Pr²SCAN50 and Pr²SCAN69), and the effect of MP2-regularization (κPr²SCAN50) and range-separated HFX (ωPr²SCAN50) is evaluated. All optimized functionals are combined with the state-of-the-art London dispersion corrections D4 and NL. The resulting functionals are assessed comprehensively for their performance on main-group and metal-organic thermochemistry on 90 different benchmark sets containing 25800 data points. These include the extensive GMTKN55 database, additional sets for main-group chemistry, and multiple sets for transition-metal complexes including the ROST61, the MOR41, and the MOBH35 sets. As the main target of this study is the development of a broadly applicable, robust functional with low empiricism, special focus is put on variants with moderate amounts of HFX (50%) which are compared to the so far successful PWPB95-D4 (50% HFX, 20% MP2 correlation) functional. The overall best variant, ωPr²SCAN50-D4, performs well on main-group and metal-organic thermochemistry, followed by the Pr²SCAN69-D4 that offers a slight edge for metal-organic thermochemistry, and by the low HFX global double-hybrid Pr²SCAN50-D4 that performs robustly across all tested sets. All four optimized functionals, Pr²SCAN69-D4, Pr²SCAN50-D4, κPr²SCAN50-D4, and ωPr²SCAN50-D4 outperform the PWPB95-D4 functional.


London dispersion

Supplementary materials

Supporting Information
Supplementary data, statistical measures, and sample input for ORCA


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.