Single-particle and collective excitations in Zn66

Abstract

Single-particle and collective excitations in $^{66}\mathrm{Zn}$ have been investigated via the multinucleon transfer reaction, $^{26}\mathrm{Mg}(^{48}\mathrm{Ca}$, $\ensuremath{\alpha}4n\ensuremath{\gamma}$) using the Gammasphere multidetector array and the Fragment Mass Analyzer. In addition to confirming and complementing the previously known low-spin structure, a new quasirotational band comprising several stretched $E2$ transitions has been established to high spins. However, due to fragmentary nature of its decay, it was not possible to link this sequence to the low-lying states and, thus, determine the absolute excitation energies, spins, and parities unambiguously. Large-scale shell-model calculations employing the JUN45 and jj44b effective interactions are able to successfully describe the low-spin structure and herewith confirm that it is dominated by single-particle excitations. The newly established rotational cascade is compared with known superdeformed bands in the $A\ensuremath{\approx}60\text{--}70$ mass region, and with results of calculations performed within the frameworks of the cranked shell model and the adiabatic and configuration-fixed constrained covariant density functional theory and the quantum particle-rotor model.