We present a model in which core excitations within the framework of the interacting boson model are studied. First, a detailed study of high-spin states and backbending in the even-even ${}_{}{}^{154-164}{}_{}{}^{}\mathrm{Dy}$ nuclei is carried out. We also address the problem of the cutoff in the yrast $B\left(E2\right)$ values in rotational nuclei. Application, again for the even-even ${}_{}{}^{154-164}{}_{}{}^{}\mathrm{Dy}$ nuclei, is performed in detail. We also discuss the intrinsic quadrupole moments and compare them to the existing data. We relate the present description, using the classical limit expressions for a given $\mathrm{sd}$-boson Hamiltonian, to the geometrical study of the even-even Dy nuclei, which also is carried out in detail.

• Received 30 September 1983

DOI:https://doi.org/10.1103/PhysRevC.29.1428