Octupole correlations in the transitional actinides and the spdf interacting boson model - art. no. 054306

The region of light actinides (Z similar to 88,N similar to 134); which is thought to exhibit signs of stable octupole deformation, offers a real chal lenge for nuclear structure models. We study the even-even Ra-Th nuclei in the framework of the spdf interacting boson model and we find that while th e properties of the low-lying states can be understood without stable octup ole deformation, higher spin states (J greater than or similar to 12 (h) ov er bar) in some of these nuclei (e.g., Ra-226) suggest that octupole deform ation develops with increasing spin. We also discuss how octupole deformati on can arise in the rotational (dynamical symmetry) limit.