High spin states in the ${}^{85}\mathrm{Sr}$ nucleus were populated in the reaction ${}^{76}\mathrm{Ge}({}^{13}\text{C},4n)$ at a beam energy of 45 MeV. The $\gamma -\gamma$ and $\gamma -\gamma -\gamma$ coincidence measurements have been utilized to establish the level scheme of ${}^{85}\mathrm{Sr}$ up to $I^{\pi }=35/2^{-}$. Nearly 50 new $\gamma$ rays and about 25 new levels were identified and most of the previously known levels confirmed. The spin-parity assignment of the levels was made by using the directional correlations of the oriented nuclei ratios and polarization asymmetry measurements. The shell-model calculations have been performed by using two recent interactions, JUN45 and jj44b, for a detailed comparison between theoretical results and the experimental data obtained in the present work. The shell-model results are in good agreements with the experimental data and are able to explain the various features such as the odd-even staggering well. Tilted axis cranking calculations were also performed to understand the magnetic rotation (MR) phenomenon at higher spins. One of the positive-parity $\Delta I=1$ bands has been assigned a three-quasiparticle (3qp) configuration, which appears to behave like a MR band. A negative-parity band populated up to $I^{\pi }=35/2^{-}$ was also assigned a 3qp configuration at low spin and a five-quasiparticle configuration at high spin; however, it does not exhibit the expected MR features, in contrast to a similar band in the ${}^{83}\mathrm{Kr}$ nucleus.

• Received 8 April 2014
• Revised 23 June 2014

DOI:https://doi.org/10.1103/PhysRevC.90.024315