Competition between high-K states and rotational structures in ¹⁷⁷Ta

High-spin states in ¹⁷⁷Ta have been studied using the ¹⁷⁰Er(¹¹B,4n) reaction. New intrinsic states have been observed corresponding to 3-, 5-, and 7-quasiparticle high-K structures. Rotational bands built on most of the 3-and 5-quasiparticle states and some transitions above the 7-quasiparticle states have been identified. Several isomers have been found, the longest lived being the 49/2^-, 7-quasiparticle state with a meanlife of 192 μs. Configurations for the observed intrinsic states have been assigned on the basis of g_K values, alignments, and decay properties. While the properties of most of the bands are consistent with their proposed configurations, the behavior of some, including the one built on K^π = 21/2^- 3-quasiparticle isomer, is not well understood. Multiquasiparticle blocking calculations based on the Lipkin-Nogami method, are in good agreement with the excitation energies of the experimentally observed states and all the predicted states close to the yrast line up to spin 49/2 have been observed experimentally. The calculations predict the existence of a 9-quasiparticle 67/2^- yrast trap at ∼ 8.5 MeV.