VARIATION OF THE GROUND-STATE CORRELATION-ENERGY OF ATOMS WITH ATOMIC-NUMBER

The empirical correlation energy of atoms and singly charged positive and negative ions in their ground state shows a roughly linear depende nce with respect to the number of electrons. However, the deviations f rom this linear behaviour follow a well defined trend. A formulation b ased on density functional theory allows us to understand these featur es. This formulation focuses on the number of pairings between antipar allel-spin electrons in the same main shell.