Hyperfine Structure of the(5p)5(6s)P23State ofXe12954andXe13154

The hyperfine structures of the metastable ${\mathrm{}\left(5p\right)\mathrm{}}^5\mathrm{}\left(6s\right)\mathrm{}{}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$ state of ${}_{54}{}^{}{}_{}{}^{}\mathrm{Xe}_{}^{129}{}_{}{}^{}$ and ${}_{54}{}^{}{}_{}{}^{}\mathrm{Xe}_{}^{131}{}_{}{}^{}$ have been measured by the atomic beam magnetic resonance method. The zero magnetic field intervals $f(F\leftrightarrow F^{\prime })$ are: for ${\mathrm{Xe}}^{129}$, $f(\frac{3}{2}\leftrightarrow \frac{5}{2})=5961.2577\mathrm{}\left(9\right)\mathrm{}$ Mc/sec; and for ${\mathrm{Xe}}^{131}$, $f(\frac{5}{2}\leftrightarrow \frac{7}{2})=2693.6234\mathrm{}\left(7\right)\mathrm{}$ Mc/sec, $f(\frac{3}{2}\leftrightarrow \frac{5}{2})=1608.3475\mathrm{}\left(8\right)\mathrm{}$ Mc/sec, and $f(\frac{1}{2}\leftrightarrow \frac{3}{2})=838.7636\mathrm{}\left(4\right)\mathrm{}$ Mc/sec. The values of the quadrupole and octupole moments of ${\mathrm{Xe}}^{131}$, without polarization corrections and without corrections for any effects of configuration mixing, are $Q=-0.120\mathrm{}\left(12\right)\mathrm{}$ b and $\Omega =+0.048\mathrm{}\left(12\right)\mathrm{}$ nmb. The hyperfine-structure anomaly for the two isotopes due to the $s_{\frac{1}{2}}$ electron alone is $\Delta \left(s_{\frac{1}{2}}\right)=+0.0440\mathrm{}\left(44\right)\%$, in disagreement with the prediction of the single-particle model.