SHAPE COEXISTENCE AND SIGNATURE SPLITTING IN BR-77

High angular momentum states in Br-77 were populated via the Cu-65(O-1 8, alpha2n)Br-77 reaction at 65 MeV using the Florida State University (FSU) FN Tandem-LINAC accelerator. The Pitt-FSU array with 9 Compton- suppressed high purity Ge detectors was used to measure prompt gamma-g amma coincidences. Analysis of the coincidences led to an extension of the positive- and negative-parity bands to spins of (41/2+) and (43/2 -). Directional correlation of oriented nuclei ratios have been deduce d where possible, and spin assignments made accordingly. A cranked-she ll-model analysis shows that in the positive-parity band the nug9/2 al ignment occurs at the same frequency as in the neighboring isotopes, B r-75, Br-79 but with a larger interaction strength. In the negative-pa rity bands the lower pig9/2 crossing also occurs at about the same fre quency as in Br-75, but with a smaller interaction. The higher frequen cy nug9/2 crossing is delayed in Br-77. Hartree-Fock-Bogolyubov cranki ng calculations predict considerable gamma softness in Br-77, and part icle-rotor model calculations support the interpretation of gamma soft ness or variations in triaxiality within the bands.