Rigid triaxial model for depopulation of I=3 gamma vibrational band

The Davydov-Filippov Model has been employed to evaluate the B(E2) branching ratios 3+→2+/4+, 3+→2/2+' and 3+→4+/2+' depopulating I=3 gamma vibrational band of the even-even deformed nuclei in medium and heavy mass region. The results are compared with the known experimental values. An excellent fit within a factor of two has been obtained for nuclei having non-axiality parameter (γ) in the range 140<γ<280. It supports the adiabatic approximation at the energy values more than 1 MeV and favours the rigid shape of the nucleus with mean values of shape parameters β and γ. It also establishes Ksup(π)=2,1=3 level as a member of classical gamma vibrational band originating from collective excitations and, therefore, goes against the view point of Zawischa et al, who doubted the vibrational nature of even deformed nuclei