where, V mod,KS ( r) is the modified Kohn-Sham potential in which the self-energy potential related, in general, to half an electron V S ( r) is subtracted from the Kohn-Sham potential V KS ( r). The corrected V S ( r) is obtained by applying a cutoff function Θ(r) to the self-energy potential V S ( r) approximately given by the difference between the Kohn-Sham potentials for the neutral (all-electron) and half-ionized atoms as