Exact expressions for the height of the interatomic step in the exchange-correlation potential from the derivative discontinuity of the energy

Abstract

Popular approximations to the exchange-correlation (xc) energy of density functional theory do not yield the spatial `step' structures in the exact xc potential which are necessary to describe dissociation and electron excitation with the Kohn-Sham (KS) system. Via the discontinuity in the derivative of the xc energy as a function of electron number I derive exact analytic expressions in terms of the KS single-particle energies for the height of the step in the xc potential between a variety of open- and closed-shell atoms within stretched molecules.

8 pages, 8 figures

References in corpus (4)

• Localization and delocalization errors in density functional theory and implications for band-gap prediction
• Time-dependent density functional theory: Past, present, and future
• Fractional spins and static correlation error in density functional theory
• Kohn-Sham potential for a strongly correlated finite system with fractional occupancy