Abstract
Lifetimes of 30 high-spin levels in were measured using the Doppler-shift attenuation method. The high-spin states were populated using the reaction at , with a thick target used to stop all recoils. Prompt coincidences were detected using a Compton-suppressed Ge array consisting of three Clover detectors and seven single-crystal detectors. Lifetimes were determined from experimental line shapes measured at both and whenever possible. Transition quadrupole moments inferred from the lifetimes in the lowest positive- and negative-parity bands are large at low spin, but show a rather abrupt decrease at high spin. Results of calculations using the projected shell and cranked Woods-Saxon models in conjunction with the cranked-shell model suggest that these drops in are due to quasiparticle alignment, which introduce shape changes in each band from nearly prolate below the alignment to triaxial above. Magnetic dipole transition strengths in the yrast positive-parity band show a strong alternating pattern with spin, similar to that observed in other neighboring odd-odd nuclei.
1 More- Received 24 January 2004
DOI:https://doi.org/10.1103/PhysRevC.69.064314
©2004 American Physical Society