Construction of meta-GGA functionals through restoration of exact constraint adherence to regularized SCAN functionals
Abstract
The SCAN meta-GGA exchange-correlation functional [Phys. Rev. Lett. 115, 036402 (2015)] is constructed as a chemical environment-determined interpolation between two separate energy densities: one describes single orbital electron densities accurately, and another describes slowly-varying densities accurately. To conserve constraints known for the exact exchange-correlation functional, the derivatives of this interpolation vanish in the slowly-varying limit. While theoretically convenient, this choice introduces numerical challenges that degrade the functional's efficiency. We have recently reported a modification to the SCAN functional, termed rSCAN [J. Phys. Chem. Lett. 11, 8208 (2020)] that introduces two regularizations into SCAN which improve its numerical performance at the expense of not recovering the fourth order term of the slowly-varying density gradient expansion for exchange. Here we show the derivation of a progression of functionals (rSCAN, r++SCAN, rSCAN, and rSCAN) with increasing adherence to exact conditions while maintaining a smooth interpolation. The greater smoothness of rSCAN seems to lead to better general accuracy than the additional exact constraint of SCAN or rSCAN does.
Keywords
Cite
@article{arxiv.2110.00647,
title = {Construction of meta-GGA functionals through restoration of exact constraint adherence to regularized SCAN functionals},
author = {James W. Furness and Aaron D. Kaplan and Jinliang Ning and John P. Perdew and Jianwei Sun},
journal= {arXiv preprint arXiv:2110.00647},
year = {2022}
}