Interplay between Single-Particle and Collective Effects in the Odd-A Cu Isotopes beyond N=40

I. Stefanescu , G. Georgiev (1) , D. L. Balabanski , N. Blasi , A. Blazhev , N. Bree , J. Cederkäll , T. E. Cocolios , T. Davinson , J. Diriken , J. Eberth , A. Ekström , D. Fedorov , V. N. Fedosseev , L. M. Fraile , S. Franchoo (2) , K. Gladnishki , M. Huyse , O. Ivanov , V. Ivanov , J. Iwanicki , J. Jolie , T. Konstantinopoulos , Th. Kröll , R. Krücken , U. Köster , A. Lagoyannis , G. Lo Bianco , P. Maierbeck , B. A. Marsh , P. Napiorkowski , N. Patronis , D. Pauwels , G. Rainovski , P. Reiter , K. Riisager , M. Seliverstov , G. Sletten , J. van de Walle , P. van Duppen , D. Voulot , N. Warr , F. Wenander , K. Wrzosek

1 CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse
2 IPNO - Institut de Physique Nucléaire d'Orsay

Collective properties of the low-lying levels in the odd-A 67–73Cu were investigated by Coulomb excitation with radioactive beams. The beams were produced at ISOLDE and postaccelerated by REX-ISOLDE up to 2.99 MeV/u. In 67,69Cu, low-lying 1/2-, 5/2-, and 7/2- states were populated. In 71,73Cu, besides the known transitions deexciting the single-particle-like 5/2- and core-coupled 7/2- levels, gamma rays of 454 and 135 keV, respectively, were observed for the first time. Based on a reanalysis of beta-decay work and comparison with the systematics, a spin 1/2- is suggested for these excited states. Three B(E2) values were determined in each of the four isotopes. The results indicate a significant change in the structure of the odd-A Cu isotopes beyond N=40 where single-particle-like and collective levels are suggested to coexist at very low excitation energies.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

I. Stefanescu, G. Georgiev, D. L. Balabanski, N. Blasi, A. Blazhev, et al.. Interplay between Single-Particle and Collective Effects in the Odd-A Cu Isotopes beyond N=40. Physical Review Letters, 2008, 100, pp.112502. ⟨10.1103/PhysRevLett.100.112502⟩. ⟨in2p3-00273588⟩