Two-quasiparticle Configurations, Signature Inversion and the πi 13/2 x vi 13/2 Band in 176 Ir

Abstract

High-spin states have been populated in 176Ir using the 149Sm(31P,4n) reaction. Gamma-gamma coincidence techniques have allowed numerous bands up to a maximum spin of 32 to be identified. Configurations have been assigned based on spectroscopic properties such as B(M1)/B(E2) values and aligned angular momenta. Signature inversions are observed in bands based on the πh9/2⊗ vi13/2 and πi13/2⊗ vi13/2 configurations. These inversions are compared with particle-rotor model calculations and are qualitatively reproduced when a residual proton-neutron interaction is included. The shape evolution of the bands has been studied using diabatic potential energy surface calculations. A strong configuration dependence is predicted.