$g$ factors of the $9^{-}$ and ${12}^{+}$ isomeric states in ${}_{}{}^{200}{}_{}{}^{}\mathrm{Pb}$

The $g$ factors of the $9^{-}$ state (2.236 MeV, $\tau =694\mathrm{}$ nsec) and the ${12}^{+}$ state (∼3.1 MeV, $\tau =228\mathrm{}$ nsec) in ${}_{}{}^{200}{}_{}{}^{}\mathrm{Pb}$ have been measured as $g\left(9^{-}\right)=-0.030\mathrm{}\left(3\right)\mathrm{}$ and $g\left({12}^{+}\right)=-0.157\mathrm{}\left(6\right)\mathrm{}$ by a time-differential perturbed-angular-distribution technique. The states were populated by ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}({}_{}{}^7{}_{}{}^{}\mathrm{Li}, 4n){}_{}{}^{200}{}_{}{}^{}\mathrm{Pb}\left(9^{-}\right)$ and ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}({}_{}{}^7{}_{}{}^{}\mathrm{Li}, 3n){}_{}{}^{200}{}_{}{}^{}\mathrm{Pb}\left({12}^{+}\right)$ reactions with pulsed lithium beams. An in-beam superconducting magnet supplied a field of ∼60 kG. The $9^{-}$ state $g$ factor is in agreement with the additivity value obtained from empirical single-particle $g$ factors for a $({i_{\frac{13}{2}}}^{-1\mathrm{}}, {f_{\frac{5}{2}}}^{-1\mathrm{}})9^{-}$ configuration and consistent with a small anomalous orbital contribution $\delta g_l$ for the neutron. The $g$ factor for the ${12}^{+}$ state in ${}_{}{}^{200}{}_{}{}^{}\mathrm{Pb}$ is in surprisingly good agreement with those for the ${\left(i_{\frac{13}{2}}\right)}^{-2\mathrm{}}{12}^{+}$ state in ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$ and the ${i_{\frac{13}{2}}}^{-1\mathrm{}}$ state in ${}_{}{}^{205}{}_{}{}^{}\mathrm{Pb}$, in view of the possible existence of number-dependent effects.

NUCLEAR REACTIONS ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}({}_{}{}^7{}_{}{}^{}\mathrm{Li}, 4n){}_{}{}^{200}{}_{}{}^{}\mathrm{Pb}\left(9^{-}\right)$, ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}({}_{}{}^6{}_{}{}^{}\mathrm{Li}, 3n){}_{}{}^{200}{}_{}{}^{}\mathrm{Pb}\left({12}^{+}\right)$ $E_{\mathrm{Li}}=34\mathrm{}$ MeV, pulsed beam, measured spin rotation in $B=60\mathrm{}$ kG, deduced $g$.