The influence of symmetry-preserving third-order interaction terms in the Hamiltonian of the interacting boson model [O(6) limit] on the theoretical energy spectrum, on absolute and relative B(E2) values, and on the quadrupole moment of the first excited state is discussed. A comparison between theoretical and experimental data is made for the nucleus ${}_{}{}^{196}{}_{}{}^{}\mathrm{Pt}$.

• Received 30 November 1987

DOI:https://doi.org/10.1103/PhysRevC.38.414