Collectivity at N=50: 82Ge and 84Se

The neutron-rich N = 50 isotones Ge-82 and Se-84 were investigated using intermediate-energy Coulomb excitation on a Au-197 target and inelastic scattering on Be-9. As typical for intermediate-energy Coulomb excitation with projectile energies exceeding 70 MeV/nucleon, only the first 2(+) states were excited in Ge-82 and Se-84. However, in the inelastic scattering on a Be-9 target, a strong population of the first 4(+) state was observed for Se-84, while there is no indication of a similarly strong excitation of the corresponding state in the neighboring even-even isotone Ge-82. The results are discussed in the framework of systematics and shell-model calculations using three different effective interactions.