Evolution of shape and collectivity along the Ge isotopic chain: The case of Ge80

Abstract

The shape and collectivity of $^{80}\mathrm{Ge}$ were investigated via a sub-barrier-energy Coulomb excitation measurement using the JANUS setup at the NSCL ReA3 facility. The $^{80}\mathrm{Ge}$ spectroscopic quadrupole moment ${Q}_{s}({2}_{1}^{+})$ of the ${2}_{1}^{+}$ state was measured for the first time, and the precision of the $^{80}\mathrm{Ge}$ $B(E2;{0}_{1}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})$ transition strength was increased. The experimental ${Q}_{s}({2}_{1}^{+})$ value indicates a large, prolate deformation for $^{80}\mathrm{Ge}$, which is consistent with large-scale shell-model calculations performed for comparison. These results provide important benchmarks for models that try to describe nuclear shape in neutron-rich nuclei near the magic number $N=50$.