Local density approximations and momentum-space properties in light molecules and ionic solids

Abstract

Local density approximations for moments of momentum, and for exchange and correlation energies are considered. The X²Σ⁺ and C²Σ⁺ states of BeH are used to test simple functionals and, in addition, we investigate in detail the momentum-space properties of the ground state as a function of nuclear separation. Based on our various findings we obtain reliable two-body interionic potentials for solid MgO, Na₂O and MgF₂. The potentials are tested by calculating point-defect energies as well as bulk properties.