Multiparticle- and particle x octupole states in 65 149 Tb84

Abstract

Yrast-and above-yrast states in 149Tb were investigated in (c~, 6n) and (TLi, 2n) in-beam 7-ray experiments. The yrast 7-ray cascade strongly populates three-valenceparticle states involving the hx 1/2 proton and the f7/2, h9/z, or i13/2 neutron orbitals, as well as the high-spin levels formed by the couplings of the three 149Tb valence particles, to the low-lying 146Gd octupole phonon and to higher-lying proton particle-hole core excitations. The data give the (~ h 11/2 v i13/2)12 -attraction free of octupole contributions as -631 keV. The shell model with empirical two-particle-and particle-phonon residual interactions gives an excellent quantitative description of the 149Tb energy levels. It is noted that the observed highspin members of the 7chll/2vh9/zvfT/2 configuration closely resemble the lowest symmetric and mixed-symmetry representations of the $3 permutation group.

Multiparticle configurations of excited states in Lu155

“…figure 3. The ordering of the transitions is based on their measured relative intensities, after correcting for the γ-ray detection efficiency, of I(806.7) ≡ 1000, I(684.8) = 820(80) and I(328.7) = 320 (20). The 329 keV transition is observed for the first time in this work.…”

Shell model high-spin states in 67 151 Ho84

“…Ref. [3]). These parameter-free shell model calculations predict the observed levels up to 35/2-with an average deviation of 20keV, while the two maximum aligned states are calculated ~100 keV below experiment.…”

Observation of high-spin states in theN=84 nucleusEr152and comparison with shell-model calculations

“…The mixing between i, 3/2 and (f7/2@3 )13/2 has been explicitly included in calculations for nuclei around Pb [21]. It has also been discussed for the nuclei with one to three particles outside the ' Gd core: ' Gd [22], ' Gd [23], and Tb [24]. However, for the present case with six particles outside the ' Gd core it is not feasible to include the octupole state explicitly; therefore, all calculations done for configurations which include an i, 3/p neutron are less reliable.…”