Density-functional calculation of ionization energies of current-carrying atomic states

TL;DR

This paper applies current-density-functional theory to calculate ionization energies of atomic states with current, introducing a perturbative approximation and analyzing the impact of current-dependent functionals on accuracy.

Contribution

It implements a perturbative approach to current-density-functional theory for the first time and compares different current-dependent density functional parametrizations.

Findings

Perturbative approximation is numerically feasible.

Orbital currents cause small shifts in ionization energies.

Current-dependent terms are significant for modern density functional accuracy.

Abstract

Current-density-functional theory is used to calculate ionization energies of current-carrying atomic states. A perturbative approximation to full current-density-functional theory is implemented for the first time, and found to be numerically feasible. Different parametrizations for the current-dependence of the density functional are critically compared. Orbital currents in open-shell atoms turn out to produce a small shift in the ionization energies. We find that modern density functionals have reached an accuracy at which small current-related terms appearing in open-shell configurations are not negligible anymore compared to the remaining difference to experiment.