Study of spectroscopic properties of some Ni, Cu and Zn isotopes in nuclear shell model

The nuclei around the pf shell region attract much attention and interest because of observed and expected phenomena, for instance, shapecoexistence, anomalously low-lying 0 + excited states, various kinds of isomers, and double β decay. Among these, the evolution of the shell structure can be found in many nuclei. The measured mass systematic shows the narrowing of the N = 50 shell gap toward Z = 32 [1], while the persistence of the N = 50 shell closure is suggested in Ge based on the B(E2) data [2]. In Cu isotopes, the large energy gap above the 19/2 state in Cu [3] is interpreted as a support of the stability of the N = 40 shell gap. On the other hand, beyond N = 40, the low excitation energies of 1 /2 states and the measured large B(E2) values among low-lying states in Cu and Cu indicate an onset of collective effects [3]. A unified shell-model approach has contributed critically to detailed understandings and quantitative predictions in lighter-mass regions. Fukui [4] and the USD interactions [5] have been shown to be quite successful for the p shell and the sd shell, respectively. The KB3 interaction and its descendants [6,5] have been frequently used also for the pf shell but such an approach has been missing for the nuclei in the upper part of pf shell.