The perturbed-angular-distribution method has been used to measure the $g$ factor of the $\tau =122\mathrm{}\left(10\right)\mathrm{}$-nsec fission isomer in ${}_{}{}^{237}{}_{}{}^{}\mathrm{Pu}$. To eliminate unwanted perturbations, a special cubic nonparamagnetic alloy, ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$${\mathrm{Ir}}_2$, was heated to 950°C and used as the target. The quantities measured were $A_{22}=+0.21\mathrm{}\left(6\right)\mathrm{}$ and $g=-0.45\mathrm{}\left(3\right)\mathrm{}$. The $g$ factor is consistent with the $I=\frac{3}{2}$ ground state of the 871 ${\mathrm{½}}^{+}$ Nilsson orbital, and the fission anisotropy is consistent with $K=\frac{1}{2}$ at the second saddle point.

• Received 29 December 1981

DOI:https://doi.org/10.1103/PhysRevLett.48.982