Competition between high-K states and rotational structures in 177Ta -: art. no. 044321

High-spin states in Ta-177 have been studied using the Er-170(B-11,4n) 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 (1) over bar 9-/2, 7-quasiparticle state with a meanlife of 192 mu s. 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-pi = 21-/2 3-quasiparticle isomer, is not well understood. Multiquasiparticle blocking calculations based on the Lipkin-Nogami method, an 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 similar to 8.5 MeV.