ON PARTITIONING OF ENERGY FOR ATOMS, IONS, AND MOLECULES

The fact that, for neutral atoms, the interelectronic repulsion energy I is a constant fraction (∼1/3) of the total energy E is discussed in the light of several approximate energy formulas, theoretical and empirical. We then derive the asymptotic form of the non-relativistic energy of a neutral atom as E=-kZ7/3 a.u. (Z = atomic number) with k probably between 1/2(3/2)1/3 and 9/14(3/2)1/3. For 6≦Z≦90, the actual energies are in fact between these limits, while the formula implies I/E=1/3. The ratio of interelectronic repulsion energy to total electronic energy for ions and molecules is derived. © 1969 Springer-Verlag.