Description of octupole deformation dynamics in alternating parity bands of actinides

Abstract

Angular momentum dependencies of the parity splitting and electric dipole transition probabilities in the alternating parity bands of heavy nuclei have been analyzed. It is shown that these dependencies can be treated in a universal way with a single parameter of critical angular momentum, which characterizes phase transition from octupole vibrations to the stable octupole deformation. Using the simple model of axially-symmetric reflection-asymmetric mode, the analytical expressions for the parity splitting and electric dipole transitional moment have been obtained. The results are in a good agreement with the experimental data for various isotopes of Ra, Th, U, and Pu.