The high-spin structure of the ${}^{135}\mathrm{Xe}$ isotope was studied via prompt γ-ray spectroscopy in two different experiments: (i) as a fission fragment following the fission of the ${}^{226}\mathrm{Th}$ compound nucleus formed in a fusion-fission reaction and (ii) as an evaporation residue in the ${}_{136}\mathrm{Xe}(n,2n\gamma$)${}^{135}\mathrm{Xe}$ reaction. The level scheme above the previously known $11/2^{-}$ isomer was established up to 3170-keV excitation energy. A strong sequence has been firmly assigned to ${}^{135}\mathrm{Xe}$ and forms the yrast decay path including the $(15/2^{-}$) and $(19/2^{-}$) states. A much weaker sequence of γ rays has been observed and tentatively assigned to ${}^{135}\mathrm{Xe}$ and is a candidate for the off-yrast sequence that includes the $(13/2^{-}$) and $(17/2^{-}$) states, expected in the weak coupling of the $h_{11/2}$ neutron to the even-$A$ core. The experimental results are compared with predictions from shell-model calculations.

• Received 22 February 2007

DOI:https://doi.org/10.1103/PhysRevC.75.054322