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 $^{69–79}$ Zn isotope. The nuclear magnetic dipole moments and spectroscopic quadrupole moments are well reproduced by large-scale shell–model calculations in the $f_{5}pg_9$ and $fpg_9d_5$ model spaces, thus establishing the dominant term in their wave function. The magnetic moment of the intruder $|^{π}=1/2^+$ isomer in $^{79}Zn$ 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 $^{73}Zn$ suggest a strong onset of deformation at N=43 , while the progression towards $^{79}Zn$ points to the stability of the Z=28 and N=50 shell gaps, supporting the magicity of $^{78}Ni$.