Abstract
The rotational alignment of quasiparticles has been observed in the even-even and nuclei by means of heavy-ion fusion-evaporation reactions. The structures observed are compared to those found recently in . The ground-state bands of the and isotones (N=76) possess significant triaxial shapes (γ∼-25°). Rotational alignment of protons induces a shape change towards the prolate (γ=0°) shape, while neutron alignment induces a change towards the oblate (γ=-60°) collective shape. In the more deformed nucleus, band crossings are observed in both the ground-state band and the γ-vibrational band. The crossing in the ground-state band is attributed to protons, while a second band that feeds into both the ground-state band and the γ-vibrational band is built on the [ neutron-aligned configuration. In addition, negative-parity sidebands built on two-quasiproton configurations were seen in these nuclei. The systematics of the proton and neutron alignments are discussed.
- Received 12 August 1987
DOI:https://doi.org/10.1103/PhysRevC.36.2380
©1987 American Physical Society