Evolution of nuclear structure in neutron-rich odd-Zn isotopes and isomers

Collinear laser spectroscopy was performed on Zn (Z = 30) isotopes at ISOLDE, CERN. The study of hyperfine spectra of nuclei across the Zn isotopic chain, N = 33- 49, allowed the measurement of nuclear spins for the ground and isomeric states in odd-A neutron-rich nuclei up to N = 50. Exactly one long-lived (>10 ms) isomeric state has been established in each 69-⁷⁹Zn isotope. The nuclear magnetic dipole moments and spectroscopic quadrupole moments are well reproduced by large-scale shell-model calculations in the f₅pg₉ and fpg₉d₅ model spaces, thus establishing the dominant term in their wave function. The magnetic moment of the intruder I^π = 1 /2⁺ isomer in ⁷⁹Zn is reproduced only if the νs_1/2 orbital is added to the valence space, as realized in the recently developed PFSDG-U interaction. The spin and moments of the low-lying isomeric state in ⁷³Zn suggest a strong onset of deformation at N = 43, while the progression towards ⁷⁹Zn points to the stability of the Z = 28 and N = 50 shell gaps, supporting the magicity of ⁷⁸Ni.