Energy Staggering in Ground Bands of 232Th and 236,238U Nuclei Using the Interacting Vector Boson Model

Abstract

The ΔI = 2 and ΔI = 4 staggering parameters of transition energies Eγ for normally deformed positive parity ground bands in 232Th and 236,238U nuclei are studied in framework of the symplectic extension of the interacting vector boson model. The model parameters are obtained from the fitting procedure between the calculated excitation energies and the corresponding experimental ones. The staggering parameters represent the finite difference approximations to higher order derivatives dnEγ/dIn of the γ-ray transition energies in a ΔI = 2 and ΔI = 4 bands, which yielding multipoint formulae. The first order derivative (two-point formula) provides us with information about the dynamical moment of inertia. The staggering oscillation for the fourth order derivative (five-point formula) is about 0.5 KeV and is even larger than that in superdeformed bands. The quite similarity in dynamical moments of inertia of the isotopes 236,238U up to high spin states indicate that the phenomenon of identical bands is not restricted to superdeformed bands.