Evolution of shape and collectivity along the Ge isotopic chain: The case of Ge-80

The shape and collectivity of Ge-80 were investigated via a sub-barrier-energy Coulomb excitation measure- ment using the JANUS setup at the NSCL ReA3 facility. The Ge-80 spectroscopic quadrupole moment Q(s)(2(1)(+)) of the 2(1)(+) state was measured for the first time, and the precision of the Ge-80 B(E2; 0(1)(+) -> 2(1)(+)) transition strength was increased. The experimental Q(s)(2(1)(+)) value indicates a large, prolate deformation for Ge-80, 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.