Anomalies in Hyperfine Structure

The deviations from the interval rule in the hyperfine structure of two of the energy states in mercury can be explained satisfactorily as due to perturbations arising from their proximity. The forbidden line Hg I $\lambda 2967.5$ ($6s6d{}_{}{}^1{}_{}{}^{}D_2^{}{}_{}{}^{}-6s7p{}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}$) and its hyperfine structure are also explained by these perturbations. The hyperfine structure ascribed to the $3s4f$ levels of ionized aluminum which has seemed to be in contradiction with the theory, can be shown to belong partially to the $3s\mathrm{n}g$ levels and to come out in agreement with theoretical expectations.