Hfs of the5P122State ofIn115andIn113: Hfs Anomalies in the Stable Isotopes of Indium

The hfs splittings of the $5{}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$ states of ${\mathrm{In}}^{115}$ and ${\mathrm{In}}^{113}$ have been measured by the atomic-beam magnetic-resonance method. We find: $\Delta \nu \left({\mathrm{In}}^{115}\right)=[11\mathrm{}409.7506\pm \mathrm{}(20\left)\right]\times {10}^6 invsec,$ $\Delta \nu \left({\mathrm{In}}^{113}\right)=[11\mathrm{}385.4300\pm \mathrm{}(20\left)\right]\times {10}^6 invsec.$ A comparison of the ratio of the dipole coupling constants of the two isotopes in the $P_{\frac{1}{2}}$ state and in the $P_{\frac{3}{2}}$ state with the ratio of the nuclear $g_I$ factors yields the following hfs anomalies: ${\Delta }_{\frac{1}{2}}=(7.5\mathrm{}\pm 1.3)\times {10}^{-6\mathrm{}}, {\Delta }_{\frac{3}{2}}=-(23.8\mathrm{}\pm 1.3)\times {10}^{-6\mathrm{}}.$ The fractional change in the nuclear radius between ${\mathrm{In}}^{113}$ and ${\mathrm{In}}^{115}$, $\frac{\delta R}{R}$, is found to be 3.66×${10}^{-3\mathrm{}}$ as compared to 5.85×${10}^{-3\mathrm{}}$ calculated on the assumption of an incompressible nucleus.