Lifetimes of excited states in the neutron-deficient odd-odd nucleus ${}^{166}\mathrm{Re}$ have been measured for the first time using the recoil distance Doppler-shift method. The measured lifetime for the $\left(8^{-}\right)$ state; $\tau =480$ (80) ps, enabled an assessment of the multipolarities of the $\gamma$ rays depopulating this state. Information on electromagnetic transition strengths were deduced for the $\gamma$-ray transitions from the $\left(9^{-}\right),\left({10}^{-}\right)$, and $\left({11}^{-}\right)$ states, and in the case of the $\left({10}^{-}\right)$ and $\left({11}^{-}\right)$ states limits on the $B\left(M1\right)$ and $B\left(E2\right)$ strengths were estimated. The results are compared with total Routhian surface predictions and semiclassical calculations. Tilted-axis cranking calculations based on a relativistic mean-field approach (TAC-RMF) have also been performed in order to test the possibility of magnetic rotation in the ${}^{166}\mathrm{Re}$ nucleus. While the TAC-RMF calculations predict a quadrupole-deformed nuclear shape with similar ${\beta }_2$ deformation as obtained by using the TRS model, it was found that the experimental electromagnetic transition rates are in better agreement with a collective-rotational description.

• Received 29 May 2015
• Revised 24 December 2015

DOI:https://doi.org/10.1103/PhysRevC.93.034309