Low-energy states in Zn and the structure of Ni

Orlandi, R.  ; Mcher, D.*; Raabe, R.*; Jungclaus, A.*; Pain, S. D.*; Bildstein, V.*; Chapman, R.*; De Angelis, G.*; Johansen, J. G.*; Van Duppen, P.*; Andreyev, A. N.*; Bottoni, S.*; Cocolios, T. E.*; De Witte, H.*; Diriken, J.*; Elseviers, J.*; Flavigny, F.*; Gaffney, L. P.*; Gernhuser, R.*; Gottardo, A.*; Huyse, M.*; Illana, A.*; Konki, J.*; Krll, T.*; Krcken, R.*; Lane, J. F. W.*; Liberati, V.*; Marsh, B.*; Nowak, K.*; Nowacki, F.*; Pakarinen, J.*; Rapisarda, E.*; Recchia, F.*; Reiter, P.*; Roger, T.*; Sahin, E.*; Seidlitz, M.*; Sieja, K.*; Smith, J. F.*; Valiente-Dobn, J. J.*; von Schmid, M.*; Voulot, D.*; Warr, N.*; Wenander, F. K.*; Wimmer, K.*

Single-neutron states in the = 49 isotope Zn were populated in the Zn(d,p)Zn transfer reaction at REX-ISOLDE, CERN. The combined detection of protons ejected in the reaction and of rays emitted by Zn permitted the identification of the lowest-lying 5/2 and 1/2 excited states. The analysis of proton angular distributions links these states to a significant amount of single-particle strength around 1 MeV, and specifically to the d and s neutron orbits, which lie above the = 50 neutron shell gap. Comparison with large-scale-shell-model calculations supports a robust = 50 shell-closure for Ni. These data constitute a considerable step towards the understanding of the magicity of Ni and of the structure of isotopes in the region.