Non-yrast nuclear spectra in a model of coherent quadrupole-octupole motion

Abstract

A model assuming coherent quadrupole-octupole vibrations and rotations is applied to describe non-yrast energy sequences with alternating parity in several even-even nuclei from different regions, namely ${}^{152,154}$Sm, ${}^{154,156,158}$Gd, ${}^{236}$U and ${}^{100}$Mo. Within the model scheme the yrast alternating-parity band is composed by the members of the ground-state band and the lowest negative-parity levels with odd angular momenta. The non-yrast alternating-parity sequences unite levels of $\beta$-bands with higher negative-parity levels. The model description reproduces the structure of the considered alternating-parity spectra together with the observed B(E1), B(E2) and B(E3) transition probabilities within and between the different level-sequences. B(E1) and B(E3) reduced probabilities for transitions connecting states with opposite parity in the non-yrast alternating-parity bands are predicted. The implemented study outlines the limits of the considered band-coupling scheme and provides estimations about the collective energy potential which governs the quadrupole-octupole properties of the considered nuclei.

38 pages, 9 figures

References in corpus (4)

• Nuclear collective motion with a coherent coupling interaction between quadrupole and octupole modes
• Description of nuclear octupole and quadrupole deformation close to the axial symmetry: Critical-point behavior of 224Ra and 224Th
• Parity shift and beat staggering structure of octupole bands in a collective model for quadrupole-octupole deformed nuclei
• Simultaneous description of four positive and four negative parity bands

Cited by in corpus (6)

• Spectroscopy of quadrupole and octupole states in rare-earth nuclei from a Gogny force
• Spectroscopy of reflection-asymmetric nuclei with relativistic energy density functionals
• ${}^{229m}$Th isomer from a nuclear model perspective
• Microscopic core-quasiparticle coupling model for spectroscopy of odd-mass nuclei with octupole correlations
• Conjunction of $\gamma$-rigid and $\gamma$-stable collective motion in the critical point of the phase transition from spherical to deformed nuclear shapes
• The alternating-parity bands of \element{236,238}{U} and \element{238,240}{Pu} in a particle-number conserving method based on cranked shell model