Hyperfine Structure of the Stable Lithium Isotopes. I

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 $\Delta {\nu }_6=228.20528\mathrm{}\left(8\right)\mathrm{}$ Mc/sec, and of ${\mathrm{Li}}^7$ is $\Delta {\nu }_7=803.50404\mathrm{}\left(48\right)\mathrm{}$ Mc/sec. By means of these values and the value for the ratio of the $g_I\text{'}\mathrm{s}$ obtained by Klein, the hyperfine-structure anomaly was determined to be ${\Delta }_{67}=+1.065\mathrm{}\left(6\right)\mathrm{}\times {10}^{-4\mathrm{}}$. The errors quoted are four times the statistical errors.