High-spin states in $^{135}$Xe

Investigation of high-spin states in $^{135}$Xe is important for comparison with shell-model calculations because this isotope has only one neutron hole in the N=82 shell and, hence, a relatively limited number of single-particle configurations at low excitation energies. The structure of $^{135}$Xe was studied in two experiments: i) as a fission fragment following the fission of the $^{226}$Th compound nucleus formed in a fusion-fission reaction ($^{18}$O at 91~MeV on $^{208}$Pb) with the GAMMASPHERE spectrometer at LBNL, and ii) as an evaporation residue in the $^{136}$Xe(n,2n$\gamma$)$^{135}$Xe reaction with the GEANIE spectrometer at LANL. The level scheme above the 11/2$^-$, 527-keV isomer (from the odd neutron in the $h_{11/2}$ orbital) was established up to 3710-keV excitation energy. This is the first observation of negative-parity high-spin states in this isotope. A strong sequence was assigned to $^{135}$Xe and forms the yrast decay path including the 15/2$^{-}$ and 19/2$^{-}$ states. A much weaker sequence of $\gamma$-rays was tentatively assigned to $^{135}$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 results are compared with predictions from shell-model calculations.