Two-quasiparticle-plus-rotor bandmixing calculations have been performed to ascertain whether they can reproduce the phenomena of backbending and anomalous negative parity bands which have been observed in several even-even nuclei. The consequences of this model are discussed in detail for ${}_{}{}^{156}{}_{}{}^{}\mathrm{Er}$ and some results for ${}_{}{}^{104}{}_{}{}^{}\mathbf{Pd}$ are presented. The calculations reproduce the observed spectra and electromagnetic decay properties demonstrating the importance of the Stephens and Simon decoupling model. A new coupling scheme clearly emerges, for high-spin two-quasiparticle states at intermediate deformation, where both the magnitude of the intrinsic spin of the particles and its projection on the axis of rotation are approximately good quantum numbers. The residual two-quasiparticle interaction has been shown to have little influence on the high-spin behavior.

NUCLEAR STRUCTURE ${}_{}{}^{156}{}_{}{}^{}\mathrm{Er}$ and ${}_{}{}^{104}{}_{}{}^{}\mathrm{Pd}$; calculated $E_x$, wave functions, and electromagnetic properties of two-quasiparticle bands; demonstrated the applicability of the Coriolis decoupling model.

• Received 6 November 1975

DOI:https://doi.org/10.1103/PhysRevC.14.1224