Importance of complex orbitals in calculating the self-interaction-corrected ground state of atoms

TL;DR

This paper demonstrates that using complex orbitals in self-interaction-corrected density functional calculations significantly improves the accuracy of atomic ground state energies and ionization energies, highlighting the importance of orbital complexity.

Contribution

It shows that incorporating complex orbitals in self-interaction corrections enhances the accuracy of atomic energy calculations compared to real orbitals.

Findings

Complex orbitals improve total energy calculations.

Self-interaction correction aligns orbital energies with ionization energies.

Real orbitals can lead to higher total energies and worse results.

Abstract

The ground state of atoms from H to Ar was calculated using a self-interaction correction to local and gradient dependent density functionals. The correction can significantly improve the total energy and makes the orbital energies consistent with ionization energies. However, when the calculation is restricted to real orbitals, application of the self-interaction correction can give significantly higher total energy and worse results, as illustrated by the case of the Perdew-Burke-Ernzerhof gradient dependent functional. This illustrates the importance of using complex orbitals for systems described by orbital density dependent energy functionals.