We have identified several high-$K$ four- and six-quasiparticle states between 2.5 and 5 MeV excitation in ${}_{}{}^{176}{}_{}{}^{}\mathrm{Hf}$, which are well described by the collective model with axial symmetry. Isomers with $K^{\pi }={14}^{-},{19}^{+}, \mathrm{and} {22}^{-}$ form traps at or near the yrast line. The yrast structure changes from the ground band to a $K^{\pi }={16}^{+}$ band at $I=16\mathrm{}$ and again to a $K^{\pi }={22}^{-}$ state at $I=22\mathrm{}$, providing the first demonstration that intrinsic excitations of a heavy deformed nucleus can become yrast.

• Received 14 June 1976

DOI:https://doi.org/10.1103/PhysRevLett.37.823