Evidence for shape coexistence in 77Br

✍ Scribed by I. Ray; P. Banerjee; S. Bhattacharya; A. Goswami; S. Muralithar; R.P. Singh; R.K. Bhowmik

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 178 KB
• Volume: 694
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/s0375-9474(01)01086-7

✦ Synopsis

The nucleus 77 Br has been studied in the reaction 65 Cu( 16 O, 2p2n) at E = 75 MeV. Lifetimes have been measured for several states using the Doppler-shift attenuation technique. The B(E2) values for the inband transitions, deduced from the lifetime results, reflect strong collectivity for both the positive-parity yrast band (band 1) and the ground-state negative-parity band (band 2). States with spin above 17/2 + in band 1 are found to have a large average quadrupole deformation of β 2 = 0.35. The experimental results for band 2 suggest that the 25/2 -and 29/2 -states are somewhat more strongly deformed than the lower-spin states. A comparison of the experimental results with particlerotor-model calculations provides evidence for shape coexistence in 77 Br, favouring a prolate shape for the g 9/2 yrast band and an oblate shape for the lowest negative-parity band.