Configuration and unusually fast decay of theKπ=16−four-quasiparticle isomer in182Re

Abstract

High-spin states in ${}^{182}\mathrm{Re}$ were studied using the ${}^{176}\mathrm{Yb}{(}^{11}\mathrm{B},5n)$ reaction at 70 MeV. The previously known four-quasiparticle isomer at 2256 keV is assigned spin and parity of ${16}^{\ensuremath{-}}.$ The rotational band built upon this multiquasiparticle state was identified and examination of the ${(g}_{K}\ensuremath{-}{g}_{R}{)/Q}_{0}$ values revealed that it arises from the $\ensuremath{\pi}{(9/2}^{\ensuremath{-}}[514])\ensuremath{\bigotimes}{\ensuremath{\nu}}^{3}{(7/2}^{\ensuremath{-}}[514]{,7/2}^{\ensuremath{-}}[503]{,9/2}^{+}[624])$ configuration. The decay of the ${16}^{\ensuremath{-}}$ isomer is found to be less hindered when compared to those observed for similar four-quasiparticle long-lived states in neighboring odd-odd ${}^{176,178,180}\mathrm{Ta}$ isotopes. A possible explanation of this feature, involving a ``local'' mixing with a nearby ${16}^{\ensuremath{-}}$ collective state, is discussed.