Construction of exchangecorrelation functionals through interpolation between the noninteracting and the strongcorrelation limit
Abstract
Drawing on the adiabatic connection of density functional theory, exchangecorrelation functionals of KohnSham density functional theory are constructed which interpolate between the extreme limits of the electronelectron interaction strength. The first limit is the noninteracting one, where there is only exchange. The second limit is the strong correlated one, characterized as the minimum of the electronelectron repulsion energy. The exchangecorrelation energy in the strongcorrelation limit is approximated through a model for the exchangecorrelation hole that is referred to as nonlocalradius model [L. O. Wagner and P. GoriGiorgi, Phys. Rev. A 90, 052512 (2014)]. Using the noninteracting and strongcorrelated extremes, various interpolation schemes are presented that yield new approximations to the adiabatic connection and thus to the exchangecorrelation energy. Some of them rely on empiricism while others do not. Several of the proposed approximations yield the exact exchangecorrelation energy for oneelectron systems where local and semilocal approximations often fail badly. Other proposed approximations generalize existing global hybrids by using a fraction of the exchangecorrelation energy in the strongcorrelation limit to replace an equal fraction of the semilocal approximation to the exchangecorrelation energy in the strongcorrelation limit. The performance of the proposed approximations is evaluated for molecular atomization energies, total atomic energies, and ionization potentials.
 Publication:

Journal of Chemical Physics
 Pub Date:
 September 2015
 DOI:
 10.1063/1.4931160
 Bibcode:
 2015JChPh.143l4103Z