Applications of coordinate-scaling procedures to the exchange-correlation energy

Abstract

Coordinate scaling within the coupling-constant integration formula is used to determine simple approximations to the exchange-correlation energy functional ${\mathit{E}}_{\mathrm{xc}}$[ρ]. Correlation contributions to the kinetic energy, ${\mathit{T}}_{\mathrm{c}}$, are also determined by coordinate scaling. Calculations show that the approximations generated for ${\mathit{E}}_{\mathrm{xc}}$[ρ] give surprisingly good results for the species tested, considering the simplicity of the functionals, considering the fact that their forms are unorthodox, and considering the fact that they satisfy only a small fraction of the conditions known to be satisfied by the exact ${\mathit{E}}_{\mathrm{xc}}$[ρ]. The approximate functionals for ${\mathit{T}}_{\mathrm{c}}$ give reasonable values.