Low- and high-spin states of ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ge}$ are investigated through in-beam $\gamma$-ray spectroscopy via the ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},2p)$, ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}({}_{}{}^7{}_{}{}^{}\mathrm{Li},2n)$, and ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}({}_{}{}^{19}{}_{}{}^{}\mathrm{F},p2n)$ reactions. A surprising richness of collective bands is observed in ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ge}$ including three even parity bands built on $8^{+}$ levels, the lower two of which are assigned as rotational aligned bands built on both proton and neutron ${\left(g_{\frac{9}{2}}\right)}^2$ configurations, and three odd parity bands built on $\pi$ and $\nu$ configurations that include the $g_{\frac{9}{2}}$ orbit. Details of the multiple bands and other levels observed in ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ge}$ are presented. Rotation-aligned model calculations and interacting boson model calculations for ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ge}$ are also described.

NUCLEAR REACTIONS ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},2p)$, $E=39\mathrm{}$ MeV; ${}_{}{}^{63}{}_{}{}^{}\mathrm{Cu}({}_{}{}^7{}_{}{}^{}\mathrm{Li},2n)$, $E=18\mathrm{}$ MeV; ${}_{}{}^{52}{}_{}{}^{}\mathrm{Cr}({}_{}{}^{19}{}_{}{}^{}\mathrm{F},p2n)$, $E=50\mathrm{}$ MeV. Measured $E_{\gamma }$, $I_{\gamma }$, $\gamma \left(\theta \right)$, $\gamma -\gamma \left(\theta \right)$, $P$, Doppler line shapes. ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ge}$ levels, $J$, $\pi$, $\delta$, $T_{\frac{1}{2}}$ deduced. IBA calculations, RAL calculations.

• Received 14 July 1980

DOI:https://doi.org/10.1103/PhysRevC.23.213