II=2 Nuclear Staggering in Superdeformed Rotational Bands
A four parameters model including collective rotational energies to fourth order is applied to reproduce the ΔI=2 staggering in transition energies in four selected super deformed rotational bands, namely, 148Gd (SD6), 194Hg (SD1, SD2, SD3). The model parameters and the spin of the bandhead have been extracted assuming various values to the lowest spin of the bandhead at nearest integer, in order to obtain a minimum root mean square deviation between calculated and the experimental transition energies. This allows us to suggest the spin values for the energy levels which are experimentally unknown. For each band a staggering parameter represent the deviation of the transition energies from a smooth reference has been determined by calculating the fourth order derivative of the transition energies at a given spin. The staggering parameter contains five consecutive transition energies which is denoted here as the five – point formula. In order to get information about the dynamical moment of inertia, the two point formula which contains only two consecutive transition energies has been also considered. The dynamical moment of inertia decreasing with increasing rotational frequency for A∼150, while increasing for A ∼190 mass regions.
