34 μs isomer at high spin inFr212: Evidence for a many-particle octupole coupled state

A very high spin isomeric state with ${\mathrm{\tau }}_{\mathit{m}}$=34(3) μs has been observed at an excitation energy of 8.5 MeV in ${}_{}{}^{212}{}_{}{}^{}\mathrm{Fr}$. The experimental evidence favors an E3 assignment, with a very large E3 transition strength, B(E3)=100(12)×${10}^3$ ${\mathit{e}}^2$ ${\mathrm{fm}}^6$, to one of the γ rays de-exciting the isomer. The observed properties are in very good agreement with the characteristics of a ${34}^{+}$ state predicted by the multiparticle octupole vibration model.