ALIGNMENTS AND NEW BAND STRUCTURES IN THE DOUBLY ODD NUCLEUS RB-80

The high spin structure of Rb-80 has been investigated using the react ion V-51 (S-32,2pn) at a beam energy 105 MeV. The level scheme was est ablished from gamma-gamma and recoil-gamma-gamma coincidence measureme nts obtained using the Gamma Detector Array consisting of eight Compto n suppressed Ge detectors coupled to the recoil mass separator HIRA. R otational states upto an excitation energy 13 MeV and a spin 25 (h) ov er bar were studied. Band crossings at (h) over bar omega = 0.63 and 0 .73 MeV in the negative parity band,due to successive g(9/2) proton an d neutron alignment, were observed for the first time. Evidence has al so been found for a hitherto unknown sideband. The yrast positive pari ty bands in Kr-78 and Rb-80 have similar transition energies beyond a rotational frequency (h) over bar omega 0.55 MeV. This is the only kno wn example of identical bands in nuclei differing by two quasiparticle s, in this mass region. (C) 1998 Elsevier Science B.V.