Long-lived isomeric states and quasiparticle band structures in neutron-rich Gd162,164 nuclei from β decay

Neutron-rich nuclei $^{162,164}\mathrm{Eu}$ were produced by bombarding a proton beam on a $^{238}\mathrm{U}$ target at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory and mass separating the $^{162,164}\mathrm{Eu}$ products. New level schemes and new $\ensuremath{\gamma}$-ray transitions of the daughters $^{162,164}\mathrm{Gd}$ were identified from $\ensuremath{\beta}$-decay spectroscopy studies. Half-lives of the $^{162,164}\mathrm{Eu}$ were remeasured to clarify the previous ambiguous results. Two quasiparticle band structures were built and compared with neighboring nuclei. The $\ensuremath{\beta}$ and $\ensuremath{\gamma}$ bands were extended in $^{162}\mathrm{Gd}$ and a $\ensuremath{\gamma}$ band was extended in $^{164}\mathrm{Gd}$. Half-lives of the isomeric states at (${6}^{\ensuremath{-}}$) 1449 keV in $^{162}\mathrm{Gd}$ and (${4}^{\ensuremath{-}}$) 1096 keV in $^{164}\mathrm{Gd}$ were measured to be 99(3) $\ensuremath{\mu}\mathrm{s}$ and 0.56(3) $\ensuremath{\mu}\mathrm{s}$, respectively. Projected shell model calculations were performed and found to be in good agreement with all of the experimental data.