Structure ofZn76fromCu76decay and systematics of neutron-rich Zn nuclei

The first postulation of excited states in neutron-rich ${}_{}{}^{76}{}_{}{}^{}\mathrm{Zn}$ is presented. We postulate the levels in ${}_{}{}^{76}{}_{}{}^{}\mathrm{Zn}$ to be populated by high- and low-spin isomers of ${}_{}{}^{76}{}_{}{}^{}\mathrm{Cu}$ with half-lives of 0.57 s and 1.27 s, respectively. Of 12 γ rays attributed to ${}_{}{}^{76}{}_{}{}^{}\mathrm{Zn}$ decay, 11 are placed in a level scheme for ${}_{}{}^{76}{}_{}{}^{}\mathrm{Zn}$ with eight excited states up to 3 MeV. A shell-model calculation has been carried out to reproduce the systematics of the neutron-rich Zn isotopes up to A=76. The model space involves active protons in orbitals between Z=28 and 50 and neutrons in orbitals filling the subshell between N=38 and 50.