Interacting boson model calculation of octupole states in deformed nuclei

An interacting boson model study of octupole states in deformed rare-earth nuclei is discussed. The parameters and octupole bandhead energies are given for ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{158}{}_{}{}^{}\mathrm{Gd}$, ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$, ${}_{}{}^{172}{}_{}{}^{}\mathrm{Yb}$, and ${}_{}{}^{178}{}_{}{}^{}\mathrm{Hf}$. Detailed spectra and B(E3) transition rates are presented for ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$. Reasonable agreement with experiment is obtained for eight of the nine nuclei studied.