Description of Stabilization of Octupole Deformation in Alternating-Parity Bands of Heavy Nuclei

The angular-momentum dependences are analyzed for parity splitting and electric dipole transitions in alternating-parity bands of heavy nuclei. It is shown that these dependences can be treated universally by employing a single parameter taken to be a critical angular momentum that characterizes the phase transition from octupole vibrations to a stable octupole deformation. Analytic expressions for parity splitting and the electric dipole transitional moment are obtained on the basis of a simple model. The results are compared with experimental data for various barium, cerium, and neodymium isotopes.