Gamma-spectroscopic investigations on 67Ge

By γ-γ coincidence measurements following the 57Fe(12C,2nγ) reaction at Esub(12C) = 40 MeV several new states above 1.5 MeV excitation energy in 67Ge have been established. Spin and parity assignments on the basis of the angular distribution, linear polarization and γ-ray yield function indicate very similar structures in sup(67,69)Ge. The positive-parity states can be followed up to the 17/2+ state at Esub(x) = 3.07 MeV followed by a sequence of negative-parity high-spin states at nearly the same excitation energy relative to the 9/2+ single-particle state as in the neighbouring nucleus 69Ge where these states were found to have strong single-particle admixtures. A reinvestigation of the spin of the Esub(x) = 2.75 MeV level in 69Ge resulting in a change of its spin from 15/2+ to 17/2+ and thus for all spins above, removed the discrepancy concerning the spin assignments of corresponding levels in sup(67,69)Ge. The excitation pattern of the Ge isotopes with 34 <= N <= 39 clearly indicate same structures probably due to the strong competition between collective and single-particle excitations along the whole chain similar to the results for the Zn isotopes. (orig.)