New level schemes of ${}^{141}\mathrm{Ba}$ and ${}^{139}\mathrm{Xe}$ are proposed from analysis of the gamma data from ${}^{252}\mathrm{Cf}$ spontaneous fission in Gammasphere. By analogy with the $N=85\mathrm{}$ even-odd isotones ${}^{149}\mathrm{Gd},$ ${}^{147}\mathrm{Sm},$ and ${}^{145}\mathrm{Nd},$ spins and parities were assigned to the observed excited states in ${}^{141}\mathrm{Ba}$ and ${}^{139}\mathrm{Xe}.$ Level systematics in the $N=85\mathrm{}$ even-odd isotones from Gd $\mathrm{}(Z=64\mathrm{})\mathrm{}$ to Te $\mathrm{}(Z=52\mathrm{})\mathrm{}$ are discussed. The level systematics and comparison with neighboring even-even isotopes indicate that quadrupole and octupole collectivities play a role in ${}^{141}\mathrm{Ba}$ and ${}^{139}\mathrm{Xe}.$ From Gd $\mathrm{}(Z=64\mathrm{})\mathrm{}$ to Te $\mathrm{}(Z=52\mathrm{}),$ increasing excitation energies of the ${13/2}^{+}$ states and lowering relative intensities of the positive-parity bands in the $N=85\mathrm{}$ even-odd isotones may indicate that the octupole strength is becoming weaker for the isotones when approaching the $Z=50\mathrm{}$ closed shell.

• Received 4 February 2002

DOI:https://doi.org/10.1103/PhysRevC.66.014305