chaotic motion of classical particles in axially symmetric potentials with octupole deformation

The fact that there are more prolate-deformed nuclei than oblate-deformed ones in the nature is found to be related with the chaotic motion of nucleons. The primary investigation with classical theory shows that the particle motion in the potential with oblate-plus -octupole deformation could become chaotic in the case of smaller deformation strength as compared with the case of prolate-plus-octupole deformation. The reason is that the negative curvature in the potential surface could appear in the case of smaller deformation strength for the former one rather than for the latter