E2M1Multipole Mixing Ratios of Gamma Transitions in the "Quasispherical" NucleusXe132

Abstract

The $\frac{E2\mathrm{}}{M1\mathrm{}}$ multipole mixing ratios $\delta \left(\gamma \right)=\frac{〈I_f\parallel {\overrightarrow{\mathrm{j}}}_N{\overrightarrow{\mathrm{A}}}_2^{\mathrm{}\left(E\right)\mathrm{}}\parallel I_i〉}{〈I_f\parallel {\overrightarrow{\mathrm{j}}}_N{\overrightarrow{\mathrm{A}}}_1^{\mathrm{}\left(M\right)\mathrm{}}\parallel I_i〉}$ of 10 $\gamma$ transitions in the quasispherical nucleus ${\mathrm{Xe}}^{132}$ have been measured by means of $\gamma -\gamma$ directional correlations observed with two coaxial Ge(Li) detectors. Spin assignments have been made for the levels at 1963 keV ($4^{+}$), 2110 keV ($4^{+}$), 2112 keV ($6^{+}$), 2395 keV ($4^{+}$), 2584 keV ($5^{+}$), 2589 keV (3), 2614 keV ($4^{+}$), and 2839 keV ($5^{+}$). In addition, previous spin assignments for levels below 1900 keV were confirmed. Based on the proposed spin assignments, the following values of the quadrupole-dipole mixing ratios were obtained (energies in keV): $\delta \mathrm{}\left(506\right)=-1.3\mathrm{}\pm 0.4$, $\delta \mathrm{}\left(523\right)=-0.25\mathrm{}\pm 0.15$, $\delta \mathrm{}\left(630\right)={+5.3\mathrm{}}_{-1.0\mathrm{}}^{+2.1\mathrm{}}$, $\delta \mathrm{}\left(727\right)=-0.32\mathrm{}\pm 0.04$, $\delta \mathrm{}\left(955\right)=-0.15\mathrm{}\pm 0.05$, $\delta \mathrm{}\left(1136\right)=+0.9\mathrm{}\pm 0.3$, $\delta \mathrm{}\left(1143\right)=-\left({0.04}_{-0.04\mathrm{}}^{+0.09\mathrm{}}\right)$, $\delta \mathrm{}\left(1173\right)=-0.40\mathrm{}\pm 0.15$, $\delta \mathrm{}\left(1291\right)=+0.01\mathrm{}\pm 0.08$, and $\delta \mathrm{}\left(1399\right)=+0.07\mathrm{}\pm 0.02$. The results are discussed in terms of the collective vibrational model and in terms of a quasirotational model. However, these models are of limited value in explaining the experimental data concerning the level structure and multipole transitions of ${\mathrm{Xe}}^{132}$.