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.