Band structure of Br-79

High-spin states of Br-79 have been studied in the reaction Ge-76(Li-7, (4) n gamma) at 32 MeV. A gamma-detector array with twelve Compton-suppressed H PGe detectors was used. The positive-parity yrast states, interpreted as a rotationally aligned g(9/2) proton band, and the negative-parity ground sta te band have been extended to spins of (33/2(+)) and (25/2(-)), respectivel y. Lifetime measurements indicate that both bands have a similar quadrupole deformation of beta(2) similar to 0.2. The positive-parity alpha = -1/2 ba nd has been identified. Several new inter-band transitions are observed. A cranked-shell model analysis shows that the nu g(9/2) and pi g(9/2) alignme nts occur in the positive-parity and the negative-parity bands at rotationa l frequencies of (h) over bar omega similar to 0.6 and 0.4 MeV, respectivel y. The level energies and the electromagnetic properties of the g(9/2) band can be well reproduced by a particle-rotor model calculation with an axial ly symmetric core. (C) 1999 Elsevier Science B.V.