Atomic Quadrupole Moments of the Excited States of the Rare Gases. II

In a recent paper, the atomic quadrupole shielding factor $R_{\Theta }$ has been calculated for the excited states $n{p}^5{n}^{\prime }s (n^{\prime }=n+1)$ of the rare gases, in connection with an experiment of Sandars and Stewart. The previous calculations included only the first-order term $R_{\Theta ,1\mathrm{}}$ in the perturbation ${v_1}^{\prime }(n^{\prime }s\to d)$ of the excited $n^{\prime }s$ electron. The values of $R_{\Theta ,1\mathrm{}}$ were found to be in good agreement with experiment. In the present paper, the terms of second order in ${v_1}^{\prime }$ have been evaluated. Their inclusion improves appreciably the agreement of $R_{\Theta ,\mathrm{calc}}$ with the experimental values of Sandars and Stewart, in particular for the cases of Kr and Xe.