Important corrections are proposed to earlier procedures for the calculation of quadrupole polarizabilities and antishielding factors of ions. A generalized formulation of the second-order perturbation theory for many-electron atoms and ions by Dalgarno is applied to ${\mathrm{K}}^{+}$ and ${\mathrm{Cl}}^{-}$ ions leading to increases of about 30 and 11%, respectively, over results of earlier variational calculations of the antishielding factors for these ions.

• Received 29 November 1961

DOI:https://doi.org/10.1103/PhysRev.126.594