Abstract
The low-lying band structure of has been extended to higher spins using the Al,p3nγNd and Mg,2p3nγNd reactions. Two distinct high-spin structures have been identified. The ΔJ=1 band built on the ν ground state was observed to have a band crossing at . This band crossing is associated with a loss of the moderate signature splitting found below the backbend. Cranked-shell model calculations suggest that this structure involves the alignment of a pair of protons and that the loss of signature splitting can be attributed to a shape change from a triaxial shape at low spins to a prolate axial shape above the backbend. A second ΔJ=1 band structure with no signature splitting was observed to be built on a state at 1954 keV. Values for the ratios of reduced transition rates B(M1; I →I-1)/B(E2; I→I-1) and B(M1; I→I-1)/B(E2; I→I-2) have been extracted from transitions in the two bands. Comparisons with theoretical predictions helped in the identification of the structure of the second ΔJ=1 band, which is thought to be based on a ν⊗π⊗π three-quasiparticle configuration.
- Received 4 November 1986
DOI:https://doi.org/10.1103/PhysRevC.35.959
©1987 American Physical Society