Core and valence electrons in atoms and ions: configuration interaction calculations

Abstract

The partitioning of ground-state atoms or ions into inner spherical cores with radius γb and outer valence regions extending from γb to infinity is explored with the help of the expression \(E^{\text{V}} = \frac{1}{3}(T^{\text{V}} + 2V^{\text{V}} )\) for the valence-region energy (where Tv and Vv are, respectively, the kinetic and potential energies of the ‘valence electrons’ Nv found beyond the boundary surface defined by γb) using also the appropriate expression for Eion, the energy of the ion left behind after removal of the valence electrons. Ev and Eion are meaningful only for discrete numbers, Nc, of electrons assigned to the core, namely, when the exchange integrals, Kcv, between Nc and Nv total (or at least closely approach) 0, i.e., for Nc = 2 e or Nc = 2 and 10 e for the first- or second-row elements, respectively.