The high-spin states of ${}_{}{}^{82}{}_{}{}^{}\mathrm{Y}$ have been studied up to an excitation energy ∼10 MeV and a spin of 23ħ through the ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$${(}^{27}$Al,2pn${)}^{82}$Y reaction using 92 MeV ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ beam and in-beam γ-ray spectroscopic techniques. The electromagnetic properties and the structure of high-spin states in the positive parity band and the negative parity band have been investigated through a measurement of several new lifetimes. The experimentally obtained transition quadrupole moments exhibit a transition from a near spherical shape with ${\mathit{Q}}_{\mathit{t}}$∼0.6 eb to a deformed shape with ${\mathit{Q}}_{\mathit{t}}$∼2.1 eb around a spin I∼9ħ for the positive and negative parity bands and are in reasonable agreement with those calculated using deformation parameters (β,γ) as predicted by the total Routhian surface calculations. The observed signature splitting, quasiparticle alignments, the kinematic, and dynamic moment of inertias as a function of rotational frequency ħω or spin I have been discussed within the framework of the cranked shell model and the projected Hartree-Fock calculations. The experimental and theoretical results indicate the two neutron alignment at ħω∼0.66 MeV in the positive parity band. The observed band-crossing frequency ħω∼0.67 MeV in the negative parity band also indicates two neutron alignment.

• Received 2 December 1994

DOI:https://doi.org/10.1103/PhysRevC.51.2959