Reflection-asymmetric mode in the structure of heavy nuclei

The properties and description of the reflection-asymmetric mode in heavy nuclei are discussed. Two approaches based on the collective octupole degree of freedom and the mass asymmetry mode are presented. Angular momentum dependence of the parity splitting, phase transition in alternating parity rotational band, stabilization of the reflection-asymmetric deformation with angular momentum increase and the rigidity of the reflection-asymmetric deformation are considered.