Fermi Orbital Derivatives in Self-Interaction Corrected Density Functional Theory: Applications to Closed Shell Atoms

TL;DR

This paper introduces derivatives of Fermi orbitals within a self-interaction correction framework for density functional theory, enabling accurate calculations of energies and ionization potentials in closed-shell atoms.

Contribution

It derives and tests derivatives of Fermi orbitals for self-interaction corrected DFT, improving energy minimization and accuracy for atomic systems.

Findings

Total energies match experimental data closely.

Ionization energies agree well with quantum Monte Carlo results.

Method effectively restores unitary invariance in SIC calculations.

Abstract

A recent modification of the Perdew-Zunger self-interaction-correction (SIC) to the density-functional formalism (Pederson, Ruzsinszky, Perdew) has provided a framework for explicitly restoring unitary invariance to the expression for the total energy. The formalism depends upon construction of Lowdin orthonormalized Fermi-orbitals (Luken et al) which parametrically depend on variational quasi-classical electronic positions. Derivatives of these quasi-classical electronic positions, required for efficient minimization of the self-interaction corrected energy, are derived and tested here on atoms. Total energies and ionization energies in closed-shell atoms, where correlation is less important, using the PW92 LDA functional are in very good to excellent agreement with experiment and non-relativistic Quantum-Monte-Carlo (QMC) results.