$g$ factor of the $2_1^{+}$ state of ${}^{170}\mathrm{Hf}$

The $g$ factor of the $2_1^{+}$ state of ${}^{170}\mathrm{Hf}$ was measured by perturbed γ-γ angular correlation in a static external magnetic field. The result, $g(2_1^{+})=0.28$(5), extends the systematics of $g$ factors of even-even Hf isotopes to $N=98$ and enables a better test of theoretical models. The $g(2_1^{+})$ experimental values of these isotopes exhibit a remarkable constancy as a function of neutron number. This phenomenon, which was also observed for other isotopic chains in the Gd–W range, is explained in terms of a recently proposed empirical model.

Figure 1

Total projection γ spectrum obtained in this experiment. All γ lines labeled by their energy in keV belong to the decay of ${}^{170}\mathrm{Ta}$ to ${}^{170}\mathrm{Hf}$.

Figure 2

The calculated double ratio $R$(${145}^0,B$) vs the $g$ factor, and the experimental double ratio for the 779–101 keV, $0_2^{+}\to 2_1^{+}\to 0_1^{+}$ cascade, for the two values of the magnetic field used in this experiment.

Figure 3

Systematics of $g(2_1^{+})$ data for the Hf isotopes. The results for $N=104$, 106, and 108 are from the tables of Raghavan [12] and Stone [13]. The value at $N=98$ is from this work. The predictions of the rotational and vibrational limits of the hydrodynamical model [4], the IBA-2 model [10], and the phenomenological model of Zhang et al. [5] are also presented.