Interacting boson model of collective octupole states. Pt. 1

We discuss the problem of describing low-lying collective negative-parity states within the framework of the interacting boson model. We suggest that a simultaneous description of quadrupole and octupole states in nuclei be done in terms of the group U(16), which includes f- and p-bosons in addition to the usual d- and s-bosons. We analyze the dynamical symmetries associated with the rotational limit of this model and discuss their classical (large-N) analogs. We conclude with a preliminary application of the model to the radium isotopes. (orig.)