Band crossing in 83Y revisited

Abstract

Gamma rays from the reaction 28Si( 58Ni, 3p) 83Y at a beam energy of 195 MeV were recorded in recoil-γ- and γγ-coincidence mode with the POLYTESSA array and the Daresbury recoil mass separator. The known rotational bands were extended up to probable spins 49+ 2 and 45− 2 ; many new interconnecting dipole transitions and an additional cascade were established. The bands are interpreted in terms of the cranked shell model; they exhibit two band crossings each, associated with g 9 2 neutron and proton alignment. In the negative-parity yrast bands a strong signature inversion with Δe′=−100 keV and a crossing pattern alternating in the favoured and unfavoured band develop. Hartree-Fock-Bogolyubov cranking calculations with a Woods-Saxon single-particle potential have been performed to illustrate the various shape changes and explain this signature inversion.