Hyperfine Structure of the Stable Lithium Isotopes. I

Abstract

The atomic-beam magnetic-resonance technique was used to determine the hyperfine-structure separations and the hyperfine-structure anomaly between the isotopes ${\mathrm{Li}}^{6}$ and ${\mathrm{Li}}^{7}$ in the $^{2}S_{\frac{1}{2}}$ ground state. The separated-oscillatory-field method of Ramsey was used to determine the hyperfine-structure separations. The hfs of ${\mathrm{Li}}^{6}$ is $\ensuremath{\Delta}{\ensuremath{\nu}}_{6}=228.20528(8)$ Mc/sec, and of ${\mathrm{Li}}^{7}$ is $\ensuremath{\Delta}{\ensuremath{\nu}}_{7}=803.50404(48)$ Mc/sec. By means of these values and the value for the ratio of the ${g}_{I}'\mathrm{s}$ obtained by Klein, the hyperfine-structure anomaly was determined to be ${\ensuremath{\Delta}}_{67}=+1.065(6)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. The errors quoted are four times the statistical errors.