Octupole correlations in the structure of O2 bands in the N=88 nuclei150Sm Gd

Knowledge of the exact microscopic structure of the 01 + ground state and first excited 02 + state in 150Sm is required to understand the branching of double β decay to these states from 150Nd. The detailed spectroscopy of 150Sm and 152Gd has been studied using (α,xn) reactions and the γ -ray arrays AFRODITE and JUROGAM II. Consistently strong E1 transitions are observed between the excited Kπ = 02 + bands and the lowest negative parity bands in both nuclei. These results are discussed in terms of the possible permanent octupole deformation in the first excited Kπ = 02 + band and also in terms of the “tidal wave” model of Frauendorf.Web of Scienc

Congruent band structures in

We have used the ($\alpha$, 2n) and ($\alpha$, 4n) reactions and the AFRODITE $\gamma$ -ray spectrometer to make a comprehensive study of the nucleus 154Gd below \ensuremath 20\hbar . While the first excited 02 + state at 681 keV is usually considered to be the head of a \ensuremath K^{\pi}=0^{+} $\beta$ -vibrational band, we propose that the data are best described as two separate vacuum states, the ground state and the 681 keV level, each with its own $\gamma$ and octupole vibrations, pairing and alignments. The implications of this finding, for understanding the structure of transitional rare-earth nuclei, are discussed

Candidate chiral bands in (198)Tl

High-spin states in 198Tl were studied using the 197Au(α, 3n) reaction. The level scheme was considerably extended including two new bands and several non-yrast levels. One of the new bands is possibly a chiral partner to the yrast πh9/2 ⊗ νi−1 13/2 band. Two-quasiparticle-plus-triaxial-rotor model calculations suggest an aplanar orientation of the total angular momenta for these bands, thus supporting possible chirality

Possible chirality in the doubly-odd Tl-198 nucleus: Residual interaction at play

A candidate for chiral bands was found in (198)Tl for the first time in a mass region of oblate (or nonaxial with gamma >= 30 degrees) deformed nuclei. Two bands show very similar quasiparticle alignments, moments of inertia, and B(M1)/B(E2) ratios. They have a relative excitation energy of about 500 keV and different patterns of energy staggering. Calculations using the two-quasiparticle-plus-triaxial-rotor model with residual proton-neutron interaction included show that a triaxial deformation with gamma similar to 44 degrees agrees very well with all the experimental observations. Furthennore, considerable energy staggering for both partner bands was calculated for this pi h(9/2) circle times vi(13/2)(-1) configuration at gamma - 30 degrees, suggesting that chiral bands may have substantial energy staggering