On the Nuclear Moments of Lithium, Potassium, and Sodium

Abstract

The atomic beam method of zero was applied to the measurement of the nuclear spin and hfs separation of the normal $^{2}S_{\frac{1}{2}}$ state of ${\mathrm{Li}}^{7}$. The experimental arrangement was such that the precision obtained was about 1 percent. It was verified that the nuclear spin was 3/2, and the hfs separation was measured to be 0.0268\ifmmode\pm\else\textpm\fi{}0.0003 ${\mathrm{cm}}^{\ensuremath{-}1}$. By using the modified Goudsmit formula the nuclear magnetic moment was calculated to be 3.20 nuclear magnetons compared with the value of 3.28 calculated from hyperfine structure measurements on the $^{3}P_{0}\ensuremath{-}^{3}S_{1}$ group ($\ensuremath{\lambda}5485$) of ${({\mathrm{Li}}^{7})}^{+}$ by Breit and Doerman using wave functions. The same method applied to potassium and sodium yielded hfs separations of 0.0154\ifmmode\pm\else\textpm\fi{}0.0002 and 0.0596\ifmmode\pm\else\textpm\fi{}0.0006 ${\mathrm{cm}}^{\ensuremath{-}1}$, respectively, which lead to nuclear magnetic moments of 0.397 and 2.08 nuclear magnetons. With another arrangement of the apparatus yielding higher resolution than was previously obtained it was possible to set the value of 5/2 as an upper limit for the spin of the ${\mathrm{K}}^{41}$ nucleus. With the same arrangement applied to lithium it was found that the nuclear spin of ${\mathrm{Li}}^{6}$ is 2/2 or greater and that the magnetic moment of the nucleus is of the order of magnitude of that of the deuteron.