PyFLOSIC: OpenSource Implementation of the Fermi-Löwdin-Orbital Self-Interaction-Correction for use in PySCF

• Applicant: Professor Dr. Jens Kortus
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 421663657

We provided the community with an open source implementation of the Fermi-Löwdin orbital self-interaction correction (FLO-SIC) method called PyFLOSIC. In addition, we established the connection between the Fermi-orbital descriptors (FODs), being the core of FLO-SIC, to common chemical bond theories. Further, we pointed out that SIC has the need for a tighter numerical parameter space (numerical quadrature and basis set) than the underlying density functionals. These findings are especially important for application of SIC ontop of modern (meta-) GGA-functionals. Further investigations are needed to understand the numerical demands of SIC. More importantly, the nearly forgotten Linnett double-quartet (LDQ) theory was revived in context of FLO-SIC. FODs based on LDQ may lead to improved single particel densities and offer a completely new research perspective to combine SIC with chemical bonding concepts.

• DFG Programme: Research Grants