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

Phys. Rev. Lett.

100
112502
(2008)
I. Stefanescu, G. Georgiev, D.L. Balabanski, N. Blasi, A. Blazhev, N. Bree, J. Cederkäll, T.E. Cocolios, T. Davinson, J. Diriken, J. Eberth, A. Ekstöm, D. Fedorov, V.N. Fedosseev, L.M. Fraile, S. Franchoo, 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

Collective properties of the low-lying levels in the odd-𝐴  
67–73
 Cu 
  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  
67,69
 Cu 
 , low-lying 1/2−, 5/2−, and 7/2− states were populated. In  
71,73
 Cu 
 , besides the known transitions deexciting the single-particle-like 5/2− and core-coupled 7/2− levels, 𝛾 rays of 454 and 135 keV, respectively, were observed for the first time. Based on a reanalysis of 𝛽-decay work and comparison with the systematics, a spin 1/2− is suggested for these excited states. Three 𝐵⁡(𝐸⁢2) 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.

DOI
10.1103/PhysRevLett.100.112502
Published on
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