Deformed [formula omitted] bands and prolate-oblate shape coexistence in 185Tl and 187Tl

• Published in: Physics letters. B 1994-03, Vol.324 (1), p.14-19
• Main Authors: Lane, G.J., Dracoulis, G.D., Byrne, A.P., Walker, P.M., Baxter, A.M., Henry, R.G., Nisius, D., Davids, C.N., Lauritsen, T., Penttilä, H., Henderson, D.J., Sheikh, J.A., Nazarewicz, W.
• Format: Article
• Language: English
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/0370-2693(94)00073-5

High spin states in the very neutron-deficient isotopes 185Tl and 187Tl have been identified from γ-γ coincidence measurements performed with the reactions 154Gd( 35Cl, 4n) and 159Tb( 32S, 4n). Unambigous mass assignments were obtained using a Fragment Mass Analyzer and the reactions 154Gd( 36Ar, p4n and 155Gd( 36Ar, p3n). Struvtures are observed corresponding to both an i 13 2 proton coupled to a prolate deformed core, and also h 9 2 and i 13 2 protons coupled to an oblate defo rmed core. The proposed 13 2 +[606] intrinsic states are isometric, with meanlives of 12±2 ns in 185Tl and 1.0±0.2 ns in 187Tl. Eq uilibrium deformation calculations for the excitation energies of intrinsic states reproduce general trends, but overestimate the bandhead energies of high- j states.