New β -decaying state in Bi214

A new $\ensuremath{\beta}$-decaying state in $^{214}\mathrm{Bi}$ has been identified at the ISOLDE Decay Station at the CERN-ISOLDE facility. A preferred ${I}^{\ensuremath{\pi}}=({8}^{\ensuremath{-}})$ assignment was suggested for this state based on the $\ensuremath{\beta}$-decay feeding pattern to levels in $^{214}\mathrm{Po}$ and shell-model calculations. The half-life of the ${I}^{\ensuremath{\pi}}=({8}^{\ensuremath{-}})$ state was deduced to be ${T}_{1/2}=9.39(10)$ min. The deexcitation of the levels populated in $^{214}\mathrm{Po}$ by the $\ensuremath{\beta}$ decay of this state was investigated via $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ coincidences and a number of new levels and transitions was identified. Shell-model calculations for excited states in $^{214}\mathrm{Bi}$ and $^{214}\mathrm{Po}$ were performed using two different effective interactions: the H208 and the modified Kuo-Herling particle interaction. Both calculations agree on the interpretation of the new $\ensuremath{\beta}$-decaying state as an ${I}^{\ensuremath{\pi}}={8}^{\ensuremath{-}}$ isomer and allow for tentative assignment of shell-model states to several high-spin states in $^{214}\mathrm{Po}$.