Perturbative calculation of the Sternheimer anti-shielding factor with Hartree-Fock atomic orbitals

We report a calculation of the Sternheimer anti-shielding factor, \gamma, by means of first order perturbation theory. In quality of basis functions, we use Hartree-Fock electronic orbitals, expanded on hydrogenic atomic states. The computed \gamma(r) for Fe^{3+} and Cu^{1+} inner electronic cores are reported and compared with literature values, obtained from alternative methodologies.