High-spin states in ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ge}$ and ${}_{}{}^{72}{}_{}{}^{}\mathrm{Se}$ have been studied by in-beam, gamma-ray spectroscopy. In ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ge}$ the three known bands beginning at $8^{+}$ are found to exhibit crossing transitions and other new positive-parity bands are discovered to feed into them. In ${}_{}{}^{72}{}_{}{}^{}\mathrm{Se}$ only a single positive-parity yrast band is seen to high spin. Detailed, more realistic microscopic model calculations have been carried out for ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ge}$ and ${}_{}{}^{72}{}_{}{}^{}\mathrm{Se}$. There is striking agreement between the calculations and the new data for ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ge}$, including a predicted new band with superdeformation, β∼0.42. The calculations for ${}_{}{}^{72}{}_{}{}^{}\mathrm{Se}$ predict similar multiple band structures that are not seen experimentally.

• Received 10 September 1990

DOI:https://doi.org/10.1103/PhysRevC.43.2541