Electron binding energy for atoms : relativistic corrections

Abstract
Within the statistical theory a nonrelativistic binding energy for an atom with an arbitrary degree of ionization has been found with inhomogeneity of electron density taken into account. Based on Schwinger's method and using the improved estimate of the electron density at the nucleus, the analytical dependence of the leading relativistic correction on the nuclear charge Z and electron number N is obtained. The relativistic correction ~ (αZ)4 is estimated in the noninteracting electron approach. A comparison with accurate data has shown that the analytical estimates obtained give the total binding energy of an atom within 1 % for 10 ≤ N ≤ Z ≤ 100