Exploring and enhancing the accuracy of interior-scaled Perdew–Zunger self-interaction correction
The Perdew-Zunger self-interaction correction (PZ-SIC) improves the performance of density functional approximations (DFAs) for the properties that involve signi cant self-interaction error (SIE), as in stretched bond situations, but overcorrects for equilibrium properties where SIE is insigni cant. This overcorrection is often reduced by LSIC, local scaling of the PZ-SIC to the local spin density approximation (LSDA). Here we propose a new scaling factor to use in an LSIC-like approach that satis es an additional important constraint: the correct coe cient of atomic number Z in the asymptotic expansion of the exchange-correlation (xc) energy for atoms. LSIC and LSIC+ are scaled by functions of the iso-orbital indicator z , which distinguishes one-electron regions from many-electron regions. LSIC+ applied to LSDA works better for many equilibrium properties than LSDA-LSIC and the Perdew, Burke, and Ernzerhof (PBE) generalized gradient approximation (GGA), and almost as well as the strongly constrained and appropriately normed (SCAN) meta-GGA. LSDA-LSIC and LSDA-LSIC+, however, both fail to predict interaction energies involving weaker bonds, in sharp contrast to their earlier successes. It is found that more than one set of localized SIC orbitals can yield a nearly degenerate energetic description of the same multiple covalent bond, suggesting that a consistent chemical interpretation of the localized orbitals requires a new way to choose their Fermi orbital descriptors. To make a locally scaled-down SIC to functionals beyond LSDA requires a gauge transformation of the functional's energy density. The resulting SCAN-sdSIC, evaluated on SCAN-SIC total and localized orbital densities, leads to an acceptable description of many equilibrium properties including the dissociation energies of weak bonds.
- Research Organization:
- Central Michigan Univ., Mount Pleasant, MI (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; National Science Foundation (NSF); USDOE
- Grant/Contract Number:
- SC0018331; DMR-1939528; 1625061; SC0012575
- OSTI ID:
- 1770567
- Alternate ID(s):
- OSTI ID: 1768643; OSTI ID: 1781836
- Journal Information:
- Journal of Chemical Physics, Vol. 154, Issue 9; ISSN 0021-9606
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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