Structural changes in $^{78}$Ge

The nuclear structure of Ge isotopes when approaching the N=50 shell closure was investigated at the ATLAS facility at Argonne National Laboratory using the GAMMASPHERE detector array following deep-inelastic reactions. The structure of $^{78}$Ge appears to differ significantly from that observed in the stable $^{72,74,76}$Ge isotopes. In particular, a sequence of states linked by dipole transitions has been observed. It shows some properties suggestive of a gamma vibration, like in the lighter Ge isotopes, but the absence of quadrupole cross-over transitions is notable. Possible interpretations of this structure will be discussed. In addition, new information on the $^{80}$Ge nucleus will be presented, including clarification of spin assignments owing to the recently identified presence of two $\beta$-decaying isomers from $^{80}$Ga\footnote{D. Verney \it{et al.}, Phys. Rev C \textbf{87}, 054307 (2013).}.