Collective model description of parity-doublet bands in odd mass nuclei

Abstract

The yrast parity doublet rotational bands in odd medium mass and heavy nuclei are described by a quadrupole–octupole axially symmetric collective model within the strong coupling assumption regarding the odd nucleon. Energy levels of the same spin and opposite parity are interpreted as symmetric and antisymmetric quantum states of the quadrupole–octupole shape fluctuation. The energy spectrum and the associated electromagnetic transitions of the parity doublet bands observed in 21 selected nuclei, are reproduced with a very good accuracy. Predictions are performed for energies of unobserved states and electromagnetic properties. The model parameters are used to establish the static or dynamic nature of the octupole correlations in the ground state and their evolution with spin. A general systematization of the octupole effects as a function of nucleon numbers is realized in conjunction with results on even–even nuclei.