Abstract

Excited states of $^{122}\mathrm{Xe}$ populated via ${\ensuremath{\beta}}^{+}$ and electron capture (EC) decay of $^{122}\mathrm{Cs}$ have been studied with $\ensuremath{\gamma}$-ray spectroscopy using the $8\ensuremath{\pi}$ spectrometer at the TRIUMF Isotope Separator and Accelerator facility. Two sets of data were collected to optimize the signal-to-background ratio for decays of the ground (${t}_{1/2}=21.2$ s) and isomeric (${t}_{1/2}=3.7$ min) states of $^{122}\mathrm{Cs}$. The data collected have enabled the observation of 520 transitions and 191 levels, including eight new excited ${0}^{+}$ states in $^{122}\mathrm{Xe}$. The $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ angular correlations have been analyzed that permitted the assignment or restriction of the spins for 66 levels. The $E2/M1$ multipolarity mixing ratios for 38 $\ensuremath{\gamma}$-ray transitions were also extracted from these analyses. Low-spin members of the ${0}_{2}^{+}, {0}_{3}^{+}, {0}_{4}^{+}$, and ${K}^{\ensuremath{\pi}}={4}^{+}$ bands are assigned, as well as suggested ${K}^{\ensuremath{\pi}}={2}_{2}^{+}$ and ${K}^{\ensuremath{\pi}}={2}_{3}^{+}$ bandheads. Combined with previous results for high-spin states, rotational bands built on a newly assigned ${K}^{\ensuremath{\pi}}={3}_{1}^{\ensuremath{-}}$ state and its ${4}_{1}^{\ensuremath{-}}$ signature partner, the ${5}_{2}^{\ensuremath{-}}$ and its ${6}_{2}^{\ensuremath{-}}$ signature partner, are suggested. The results for the positive-parity bands are compared with a model using a general Bohr Hamiltonian derived from a mean-field theory based on the UNEDF0 energy-density functional that displays good overall agreement.