Effect of spin on nuclear shape in deformed even nuclei in the framework of asymmetric rotor model

The existence of static triaxial shape has been investigated in the framework of Davydov et al model. The assumption of rigid shape of the nucleus with fixed shape parameters β and γ proves to be satisfactory as an approximation to the actual nuclear wave functions up to spin 4. But at spin 6, the nucleus gets rid of its rigid shape, attains more freedom and the β-vibrations begin to influence the shape of the nucleus. This fact implies appreciable dynamic triaxiality for most of the even nuclei at higher angular momentum and differs from viewpoint of RJ Turner and T Kishimoto (1973) about the abrupt phase transition of the rotational mode from axially symmetric to asymmetric shape at I = 8. (author)