Level lifetimes were measured for the first time for the neutron-rich isotope ${}_{}{}^{78}{}_{}{}^{}\mathrm{Ge}$ by the fast electronic scintillation timing technique and B(E2) values were extracted. The energies of the low-lying states and the B(E2) values between the $0^{+}$ and $2^{+}$ states disclose a rapidly changing structure near N=40, followed by a stabilization, with ${}_{}{}^{74\mathrm{-}78}{}_{}{}^{}\mathrm{Ge}$ best understood as asymmetric rotors.

• Received 3 August 1992

DOI:https://doi.org/10.1103/PhysRevC.47.157