E2M1Multipole Mixing Ratios ofγTransitions in Even-Even Deformed Nuclei

A summary is presented of the magnitudes and phases of previously measured $\frac{E2}{M1}$ multipole mixing ratios of $\gamma$ transitions deexciting levels of the $\beta$- and $\gamma$-vibrational bands to the ground-state band in even-even deformed nuclei. A uniform phase, with few exceptions, is characteristic of transitions depopulating the $\gamma$ band, while no systematic behavior is apparent for transitions from the $\beta$ band; the magnitudes, while uniformly large, show little apparent systematic behavior among the nuclei in this region. Although none of the previously proposed theoretical interpretations is sufficient to explain both the magnitudes and relative phases of these mixing ratios, a phenomenological interpretation in terms of $\Delta K=1\mathrm{}$ band mixing through the intermediary of a $K=1^{+}$ excitation is successful in predicting the relative magnitudes and phases in a number of cases.