title: Universal correction for the Becke-Johnson exchange potential.
abstract: The Becke-Johnson exchange potential [A. D. Becke and E. R. Johnson, J. Chem. Phys. 124, 221101 (2006)] has been successfully used in electronic structure calculations within density-functional theory. However, in its original form, the potential may dramatically fail in systems with non-Coulombic external potentials, or in the presence of external magnetic or electric fields. Here, we provide a system-independent correction to the Becke-Johnson approximation by (i) enforcing its gauge-invariance and (ii) making it exact for any single-electron system. The resulting approximation is then better designed to deal with current-carrying states and recovers the correct asymptotic behavior for systems with any number of electrons. Tests of the resulting corrected exchange potential show very good results for a hydrogen chain in an electric field and for a four-electron harmonium in a magnetic field.
authors.affiliation: Department of Physics, Nanoscience Center, University of Jyväskylä, FI-40014 Jyvaskyla, Finland. erasanen@jyu.fi
authors.forename: E
authors.initials: E
authors.lastname: Räsänen
authors.forename: S
authors.initials: S
authors.lastname: Pittalis
authors.forename: C R
authors.initials: CR
authors.lastname: Proetto