First observation of excited states in Te-137 and the extent of octupole instability in the lanthanides

作者：Urban W^*; Korgul A; Rzaca Urban T; Schulz N; Bentaleb M; Lubkiewicz E; Durell JL; Leddy MJ; Jones MA; Phillips WR; Smith AG; Varley BJ; Ahmad I; Morss LR

来源：Physical Review C, 2000, 61(4): 041301.

DOI：10.1103/PhysRevC.61.041301

Excited states in Te-137, populated in spontaneous fission of Cm-248, were studied by means of prompt-gamma spectroscopy, using the EUROGAM2 multidetector array. This is the first observation of excited states in Te-137. The yrast excitations of Te-137 are due to the three valence neutrons. occupying the nu f(7/2) and nu h(9/2) orbitals, similarly as observed in its heavier N = 85 isotones. Systematic comparison of excited levels in the N = 85 isotones shows inconsistencies in spin and parity assignments in Xe-139 and Ba-141 nuclei. The new data for Te-137 do not confirm earlier suggestions that octupole correlations increase in the N = 85 isotones, close to the Z = 50 closed shell.

• 出版日期2000-4