Remarks on the shape transition from spherical to deformed gamma unstable nuclei

Energies and transition probabilities for low lying states in 134Ba and 104Ru were calculated within a hybrid model. The ground and the first 2+ states are described alternatively as a harmonic and anharmonic vibrator states with the remaining states as states with E(5) symmetry. Results for 134Ba are compared with those predicted by some other methods. One concludes that a gradual setting of the 'critical' potential yields a better agreement with the experimental data. Very good agreement with the data is obtained for 104Ru. Comparing the present results with those of E(5) symmetry, it is conspicuous that the present formalism adds corrections to the E(5) formalism by bringing the predictions closer to the experimental data. An analytical relationship between the states with U(5) symmetry and those given by the E(5) description is established.