Nuclear Physics A571 (1994) 253-264 North-Holland NUCLEAR PHYSICS A Structure of doubly odd bromine isotopes A = 80,82 R. Sahu zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQ Physics Department, Berhampur University,Berhampur-760 007, Orissa, India S.P. Pandya Physical Research Laboratory, Ahmedabad-380 009, India Received 18 September 1992 (Revised 29 March 1993) zyxwvutsrqponmlkjihgfedcbaZYXWVUT AlJShCt The deformed configuration mixing shell model based on Hartree-Fock states is used to study the structure of the doubly odd nuclei *“~82Br.The calculated negative and positive parity bands agree quite well with experiment in 82Br. A number of collective bands are also predicted for both nuclei. 1. Introduction In the last few years, the study of nuclei in the mass region A = 80 has been carried out very actively. These nuclei reveal very interesting patterns of deformation, bands of collective excitations and of systematics. The deformation appears to be maximum for N, Z being near 40 and decreases as the nucleon numbers decrease or increase. Bromine isotopes form an interesting sequence since the proton number is 35 and neutron number can vary from 35 to near 50. Previous theoretical calculations [ 1] have indicated that one may expect rapid shape and deformation changes in this region; in particular around Z = 34,36, oblate shapes may be more stable than prolate shapes, whereas for nucleon numbers 38-40, the prolate shapes would be favoured. One can, therefore, trace in a systematic manner the deformations and quasiparticle configurations giving rise to various bands. Also in this region, as a result of deformations, one sees rapid changes in the Fermi surface, with the parity of the last occupied orbit changing with the increase of one or two neutrons only. This results in very interesting changes in the spectroscopic structures of neighbouring nuclei. In particular, the doubly odd nuclei have a very rich structure and give a valuable insight into both the proton and the neutron configurations at different excitation energies and the nature of the mean field which result in these states. These nuclei, therefore, present a greater challenge to theorists. Several experimental studies of odd-odd isotopes of bromine have been done and some useful systematics have been summarized by Funke et al. [2,3]. We describe, in this work, a microscopic approach to understand the structure of the collective states of bromine 0315-9474/94/S 07.00 @ 1994 - Elsevier Science B.V. All rights reserved SSDZ0375-9474(93)E0646-P