Sternheimer Shielding-Antishielding. II

Abstract

The Sternheimer shielding-antishielding parameters are reported for 77 ions in $3d$, $4d$, $5d$, and $5f$ groups, as well as for gold and lithium atoms. The parameters $\lambda$ and $R$, which take into account, respectively, the effect of the core electrons on the quadrupole perturbing potential outside the ion and within the ion (owing to unfilled valence-shell electrons), have been calculated for varying ionic charge and varying atomic number in each group. The electronic wave functions used throughout the work are of the nonrelativistic Hartree-Fock-Slater type. Interesting differences of the results in each group are seen to be the values of Sternheimer parameters and ${\alpha }_q$ for ions with and without the closed-shell configurations. Also, for the lithium atom with $1s^{2}2p^1$ configuration we obtained $1-{\lambda }_0=3.46\mathrm{}$, assuming $2p^1$-shell perturbation to be one-sixth that of the closed $p$ shell. This value, incidentally, is the same as that measured recently by Anderson and Karra for the lithium ion (${\mathrm{Li}}^{+}$) in LiF. For gold atoms the configurations $5d^{10}6p^1$ and $5d^{10}6s^1$ were considered and we obtained the ratios of atomic core $5p_{\frac{3}{2}} \mathrm{to} 4p_{\frac{3}{2}}$ energy-level splittings as 1.6 and 1.7, respectively, against approximately 2 determined experimentally by Novakov and Hollander for Au in gold-cyanide compounds. The significance of these calculations is emphasized by the possibility of experimentally determining the quadrupole splittings of the atomic core by high-resolution electron spectroscopy.