Shape changes and electromagnetic properties of odd-proton rare-earth nuclei

摘要

Very rapidly rotating odd-proton and odd-odd rare earth nuclei have been studied using in-beam gamma-ray spectroscopy following heavy-ion reactions. The nucleus 171Re was studied using the reaction 123Sb(52Cr,4n)171Re. A back-bend in the proton i13/2 band was fully delineated for the first time, a second back-bend was observed in the 5/2+(402) band and other bands were extended to higher spin. Band crossings were interpreted using the Cranked Shell Model and three-band mixing calculations. Deformations as functions of spin, based on diabatic configurations, have been calculated for proton i13/2 and h9/2 bands in Re and Ir isotopes. The nuclei 173,174Ta were studied using a 19F beam on a 160Gd target. A total of 16 bands have been identified and interpreted in terms of different quasiparticle excitations. Weak interband transitions between the pseudospin doublet, composed of the 5/2+(402) and 7/2+(404) band, together with accurately measured intraband mixing ratios were compared with particle-rotor calculations. A total of 10 rotational bands were identified in the odd-odd nucleus 174Ta. 38 refs, 20 figs, 3 tabs. (Atomindex citation 26:039019)