Based on recent experimental data, the band structure of the odd-odd nucleus ${}^{86}$Y has been studied. The positive-parity yrast band built on the configuration $\pi g_{9/2}\otimes \nu g_{9/2}^{-1}$ shows a large signature splitting, and a signature inversion occurs at $I\sim 13\hslash$. The signature inversion is interpreted by the competition between single-particle and collective excitations in this nucleus. The negative-parity dipole band, which is probably connected with magnetic rotation, is assigned to the configurations $\pi g_{9/2}^2{(p_{3/2}/f_{5/2})}^{-1}\otimes \nu g_{9/2}^{-1}$ before and to $\pi g_{9/2}^2{(p_{3/2}/f_{5/2})}^{-1}\otimes \nu g_{9/2}^{-3}$ after the alignment. Self-consistent titled axis cranking calculations based on relativistic mean-field theory are performed to interpret the rotational structure. Characteristic features of magnetic rotation are found for the negative-parity band.

• Received 13 March 2013

DOI:https://doi.org/10.1103/PhysRevC.88.014317