On the Nuclear Moments of Indium

Abstract

The atomic beam method of zero moments has been applied to measure the nuclear spin, the h.f.s. $\ensuremath{\Delta}\ensuremath{\nu}$ of the normal $^{2}P_{\frac{1}{2}}$ state and the absolute magnetic moment of In 115. The spin was found to be 9/2 and the $\ensuremath{\Delta}\ensuremath{\nu}=0.381$ ${\mathrm{cm}}^{\ensuremath{-}1}$ in agreement with spectroscopic results. The resolving power which was attained was sufficiently high to allow a measurement of the fine structure of the zero moment peaks. From the separation of the two $m=\ensuremath{-}3$ peaks and the diamagnetic susceptibility, we calculate the moment of indium 115 to be 6.40\ifmmode\pm\else\textpm\fi{}0.20 nuclear magnetons. From the theory of this effect which is given below, it is clear that this value does not depend on any assumption with regard to the interaction between the nuclear spin and the electron configuration. Peaks arising from the metastable $^{2}P_{\frac{3}{2}}$ state, lying 2212.6 ${\mathrm{cm}}^{\ensuremath{-}1}$ above the $^{2}P_{\frac{1}{2}}$ state were found. The intensity of these peaks is in good agreement with what is expected from quantum statistics. Their exact location will permit an evaluation of the nuclear quadrupole moment.