title: Symmetric Nonlocal Weighted Density Approximations from the Exchange-Correlation Hole of the Uniform Electron Gas.
abstract: Nonlocal exchange-correlation energy functionals are constructed using the accurate model exchange-correlation hole for the uniform electron gas developed by Gori-Giorgi and Perdew. The exchange-correlation hole is constrained to be symmetric and normalized, so the resulting functionals can be viewed as symmetrized versions of the weighted density approximation; we call them two-point weighted density approximations. Even without optimization of parameters or functional forms, the exchange-correlation energies for small molecules are competitive with those of the best generalized gradient approximation functionals. Two-point weighted density approximations seem to be an interesting new direction for functional development. A more general version of the conditions that define the energy for fractional electron number and fractional spin are presented. These "generalized flat-planes" conditions are closely linked to the normalization of the spin-resolved exchange-correlation hole at noninteger electron number. This and many other properties of the exact exchange-correlation functional can be imposed straightforwardly and directly in symmetrized weighted density approximation.
authors.affiliation: Department of Chemistry and Chemical Biology, McMaster University , Hamilton, Ontario, Canada.
authors.forename: Rogelio
authors.initials: R
authors.lastname: Cuevas-Saavedra
authors.affiliation: Department of Chemistry and Chemical Biology, McMaster University , Hamilton, Ontario, Canada.
authors.forename: Debajit
authors.initials: D
authors.lastname: Chakraborty
authors.affiliation: Department of Chemistry and Chemical Biology, McMaster University , Hamilton, Ontario, Canada.
authors.forename: Sandra
authors.initials: S
authors.lastname: Rabi
authors.affiliation: Departamento de Física, Facultad de Ciencias, Universidad de Chile , 653-Santiago, Chile.
authors.forename: Carlos
authors.initials: C
authors.lastname: Cárdenas
authors.affiliation: Department of Chemistry and Chemical Biology, McMaster University , Hamilton, Ontario, Canada.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Ayers