SHELL STRUCTURE OF ATOMS

The average local electrostatic potential function, V(r)/rho(r), is ca lculated for 87 atoms and the corresponding mono-positive and mononega tive ions in the ground state, using the nonrelativistic average-over- configuration numerical Hartree-Fock density. It is found in general t hat the shell boundaries are expressed as the successively increasing maxima in V(r)/rho(r) and the outermost maximum presents good approxim ate estimates of the core-valence separation in atoms. The reason for such behaviour is explained analytically. The proposed function is ide ntified as the inverse of charge capacity per unit volume which attain s a maximum at the shell boundary.