The hyperfine structure of the 3067-Å line of 15-d ${}_{}{}^{205}{}_{}{}^{}\mathrm{Bi}$ was measured by optical spectroscopy. The results are $A\left({}_{}{}^4{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}\right)=166\mathrm{}\left(4\right)\mathrm{}\times {10}^{-3\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$, giving $\mu =4.13\mathrm{}\left(11\right)\mathrm{}{\mu }_N$, and 192(14) × ${10}^{-3\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$ for the ${}_{}{}^{205}{}_{}{}^{}\mathrm{Bi}$-${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ isotope shift. A reexamination of the ${}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}$ hfs shows accord with previous spectroscopic results [$\mu =4.07\mathrm{}\left(2\right)\mathrm{}{\mu }_N$], but not with the recent nuclear orientation finding by Johnston, Kaplan, and Stone that $\mu \left({}_{}{}^{207}{}_{}{}^{}\mathrm{Bi}\right)$ is substantially larger than $\mu \left({}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}\right)$. Calculations of magnetic moments of odd bismuth isotopes, including configuration mixing and pion-exchange contributions, are in agreement with our experiments.

• Received 21 October 1974

DOI:https://doi.org/10.1103/PhysRevLett.34.625