DOI 10.1140/epja/i2002-10011-3 Eur. Phys. J. A 14, 317–348 (2002) T HE EUROPEAN P HYSICAL JOURNAL A c  Societ` a Italiana di Fisica Springer-Verlag 2002 Evolution of shapes in 59 Cu C. Andreoiu 1, a , D. Rudolph 1 , I. Ragnarsson 2 , C. Fahlander 1 , R.A.E. Austin 3 , M.P. Carpenter 4 , R.M. Clark 5 , J. Ekman 1 , R.V.F. Janssens 4 , T.L. Khoo 4 , F.G. Kondev 4, b , T. Lauritsen 4 , T. Rodinger 3 , D.G. Sarantites 6 , D. Seweryniak 4 , T. Steinhardt 7 , C.E. Svensson 5, c , O. Thelen 7 , and J.C. Waddington 3 1 Department of Physics, Lund University, S-22100 Lund, Sweden 2 Department of Mathematical Physics, Lund Institute of Technology, S-22100 Lund, Sweden 3 Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada L8S 4M1 4 Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA 5 Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA 6 Chemistry Department, Washington University, St. Louis, MO 63130, USA 7 Institut f¨ ur Kernphysik, Universit¨at zu K¨ oln, D-50937 K¨ oln, Germany Received: 15 February 2002 Communicated by D. Schwalm Abstract. High-spin states in 59 Cu were populated using the fusion-evaporation reaction 28 Si + 40 Ca at a beam energy of 122 MeV. The Gammasphere Ge-detector array in conjunction with the 4π charged-particle detector array Microball allowed for the detection of γ-rays in coincidence with evaporated light particles. The resulting extensive high-spin decay scheme of 59 Cu is presented, which comprises more than 320 γ-ray transitions connecting about 150 excited states. Their spins and parities have been assigned via directional correlations of γ-rays emitted from oriented states. Average quadrupole moments of rotational bands have been determined from the analysis of residual Doppler shifts. Shell model calculations in the fp shell are invoked to study some of the low-spin states, while the experimental characteristics of the rotational bands are analyzed in the configuration-dependent cranked Nilsson-Strutinsky (CNS) approach. PACS. 21.60.Cs Shell model – 23.20.Lv Gamma transitions and level energies – 23.20.En Angular distri- bution and correlation measurements – 27.50.+e 59 ≤ A ≤ 89 1 Introduction In recent years the study of nuclei in the vicinity of 56 Ni has revealed many exciting nuclear-structure phenomena. 56 Ni has an equal number of protons and neutrons (N = Z = 28). It is regarded as a doubly magic spherical nucleus at low spin and excitation energies due to the shell gap at particle number 28, which separates the 1f 7/2 shell from the 2p 3/2 ,1f 5/2 and 2p 1/2 shells in the upper fp shell. Hence, 56 Ni is the natural core for shell model calculations in the mass A ≈ 60 region. An interesting feature in the A ≈ 60 region is the oc- currence of deformed and superdeformed bands at rela- tively moderate spins (I ∼ 10 ) and excitation energies a Present address : Oliver Lodge Laboratory, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, UK; e-mail: ca@ns.ph.liv.ac.uk b Present address : Technology Development Division, Ar- gonne National Laboratory, IL 60439, USA. c Present address : Department of Physics, University of Guelph, Guelph, Ontario, Canada N1G 2W1. (E x ∼ 10 MeV). Following the first discovery of a superde- formed band in 62 Zn [1], well- and superdeformed bands were observed in the N = Z nuclei 56 Ni [2], 58 Cu [3], and 60 Zn [4], as well as in the N = Z + 1 nuclei 59 Cu [5] and 61 Zn [6]. The configurations of the yrast bands have the leading component f −4 7/2 ⊗ (fp) 4 ⊗ g A−56 9/2 , where A − 56 is the number of nucleons in excess of 56 Ni. The compar- ison of several collective bands led to the conclusion that their quadrupole deformations scale with the number of g 9/2 particles involved in the configuration. In contrast to other mass regions, where states in the second minimum of the nuclear potential have been iden- tified, almost all rotational bands in the mass A ≈ 60 re- gion could be connected with the normal deformed, mostly spherical states in the first minimum of the nuclear po- tential. The “doubly magic” superdeformed band in 60 Zn has been linked through stretched E2 transitions, which allowed the firm assignment of the spin and parity of the band [4]. Recently, two superdeformed bands have been firmly linked to the spherical states in 59 Cu, and their band-head spins and parities established to 25/2 + and 23/2 − , respectively [5,7].