Magnetic Moment and Hyperfine Structure Coupling of the First 2+ State inGd154

The $g$ value of the 0.123-Mev 2+ state of ${\mathrm{Gd}}^{154}$ is found to be $g=0.36\mathrm{}\pm 0.06$. The hyperfine structure constant of the same nuclear state in the ${}_{}{}^8{}_{}{}^{}S_{\frac{7}{2}}^{}{}_{}{}^{}$ ground state of ${\mathrm{Gd}}^{3+}$ in aqueous solution is determined as $a=26.4\mathrm{}\pm 5$ Mc/sec. The perturbation of the angular correlation of gamma-ray cascades proceeding through this state was studied. It is found that the perturbation in aqueous solution can be decoupled by magnetic fields either parallel to one of the gamma rays or perpendicular to the plane of observation. The perturbation in molten Gd${\mathrm{Cl}}_3$ is found to be much weaker than in solution and to be unaffected by magnetic fields. Auxiliary measurements involving the first 2+ states in ${\mathrm{Sm}}^{152}$ and ${\mathrm{Gd}}^{156}$ are described.