The electron localization function and the chemical interpretation of Fermi orbital descriptors in Fermi–Löwdin self-interaction correction calculations.

This article focuses on establishing a formal connection between Fermi orbital descriptors (FODs), used in the Fermi–Löwdin orbital self-interaction correction (FLOSIC) method, and critical points (CPs) of the electron localization function (ELF), which are key indicators of chemical bonding. Through computational analysis of 27 closed-shell molecules with various bonding types, the study demonstrates that fully relaxed FODs closely resemble ELF and a newly proposed SIC-ELF CPs, supporting the interpretation of FODs as carriers of chemical bonding information consistent with Lewis theory. The authors further show that ELF and SIC-ELF CPs can serve as effective initial guesses for FOD configurations in FLOSIC calculations, potentially reducing computational cost. This work highlights the utility of FODs as formal tools for chemical analysis within self-interaction corrected density functional theory frameworks.