Single-neutron orbits near $^{78}$Ni: Spectroscopy of the N=49 isotope $^{79}$Zn

Single-neutron states in the Z=30 , N=49 isotope 79 Zn have been populated using the 78 Zn(d, p) 79 Zn transfer reaction at REX-ISOLDE, CERN. The experimental setup allowed the combined detection of protons ejected in the reaction, and of γ rays emitted by 79 Zn. The analysis reveals that the lowest excited states populated in the reaction lie at approximately 1 MeV of excitation, and involve neutron orbits above the N=50 shell gap. From the analysis of γ -ray data and of proton angular distributions, characteristic of the amount of angular momentum transferred, a 5/2+ configuration was assigned to a state at 983 keV. Comparison with large-scale-shell-model calculations supports a robust neutron N=50 shell-closure for 78 Ni. These data constitute an important step towards the understanding of the magicity of 78 Ni and of the structure of nuclei in the region.