Ground‐state energies of closed‐shell atoms

Ground‐state energies of He, Be, and Ne isoelectronic series have been calculated. The Dirac–Hartree–Fock energy values have been corrected by adding Breit, vacuum polarization, self‐energy, nuclear mass, and electron correlation corrections. The resulting energies are compared with the experimental values. As a result, an estimate of the correlation‐relativistic cross‐term energy is obtained. The effect, for large‐ Z atoms, proves to be quite substantial.