Nuclear structure of odd-oddY82

Abstract

Excited states in $^{82}\mathrm{Y}$ have been investigated via the $^{58}\mathrm{Ni}$${(}^{28}$Si,3pn${)}^{82}$Y and $^{56}\mathrm{Fe}$${(}^{29}$Si,p2n${)}^{82}$Y reactions using beams provided by the Florida State University Tandem-LINAC with energies of 95 to 135 MeV. Particle-\ensuremath{\gamma} coincidences with a full-sphere charged-particle detector and an excitation curve were used to assign \ensuremath{\gamma} rays to $^{82}\mathrm{Y}$. The $^{56}\mathrm{Fe}$${(}^{29}$Si,p2n${)}^{82}$Y reaction at 95 MeV was used to measure \ensuremath{\gamma}-\ensuremath{\gamma} coincidences with five Compton-suppressed Ge detectors. Lifetimes in the ns and ps ranges were measured using direct timing and the Doppler-shift attenuation method. A level scheme with 39 states was constructed up to tentative spins and parities of (${15}^{\mathrm{\ensuremath{-}}}$) and (${21}^{+}$). In the positive-parity yrast band a phase reversal was observed in the signature splitting at I=10\ensuremath{\Elzxh}. The B(M1) strengths in this band alternate with signature between about 0.1 and 1.0 ${\mathrm{\ensuremath{\mu}}}_{\mathit{N}}^{2}$. The B(E2) strengths of about 90 Weisskopf units are in good agreement with those predicted by Hartree-Fock-Bogolyubov calculations. Particle-rotor calculations indicate a prolate or triaxial core shape for the positive-parity band.