QUANTITIES TS[N] AND TC[N] IN DENSITY-FUNCTIONAL THEORY

Levy's constrained-search procedure [Proc. Natl. Acad. Sci. U.S.A 76, 6062 (1979)] is employed to show how to determine Kohn-Sham and Hartree-Fock-Kohn-Sham orbitals and kinetic energies T(s) and T(c), for the two-electron, four-electron, and the general case starting from the electron density. Numerical results are presented for the species H- through F7+ and the atom Be. The Pauli potential is also determined for Be. The small differences among Kohn-Sham, Hartree-Fock, and Hartree-Fock-Kohn-Sham orbitals suggest that determination of Kohn-Sham orbitals from the density in this way is an attractive procedure for getting an orbital description from an electron density.