Ionization potentials and electron affinities in the Perdew-Zunger self-interaction corrected density-functional theory

Oleg A Vydrov; Gustavo E Scuseria

doi:10.1063/1.1897378

Ionization potentials and electron affinities in the Perdew-Zunger self-interaction corrected density-functional theory

J Chem Phys. 2005 May 8;122(18):184107. doi: 10.1063/1.1897378.

Authors

Oleg A Vydrov¹, Gustavo E Scuseria

Affiliation

¹ Department of Chemistry, Rice University, Houston, Texas 77005, USA.

PMID: 15918694
DOI: 10.1063/1.1897378

Abstract

Using a self-consistent implementation of the Perdew-Zunger self-interaction corrected (PZ-SIC) density-functional theory, we have calculated ionization potentials (IP) and electron affinities (EA) of first- and second-row atoms and a set of small molecules. Several exchange-correlation functionals were tested. IPs and EAs were obtained by two methods: as the difference in self-consistent field (SCF) energies of neutrals and ions (deltaSCF) and as negatives of highest-occupied orbital energies. We found that, except for local spin-density approximation, PZ-SIC worsens DeltaSCF IPs and EAs. On the other hand, PZ-SIC brings orbital eigenvalues into much better agreement with electron removal energies. The Perdew-Zunger SIC seems to over-correct many-electron systems; for molecules it performs worse than for atoms. We also discuss several common approximations to PZ-SIC such as spherical averaging of orbital densities in atoms.