Variation of the ground-state correlation energy of atoms with atomic number

Abstract

The empirical correlation energy of atoms and singly charged positive and negative ions in their ground state shows a roughly linear dependence with respect to the number of electrons. However, the deviations from this linear behaviour follow a well defined trend. A formulation based on density functional theory allows us to understand these features. This formulation focuses on the number of pairings between antiparallel-spin electrons in the same main shell.