Nuclear softness in the ground state rotational bands in even-even yb 158-170 nuclei

The ground state rotational band structures are studied under the aegis of Variable Moment of Inertia (VMI) Model in the even-even Yb isotopes. The nuclear softness parameter and ground state moment of inertia are obtained by applying least square fitting method. These parameters are used in VMI Model soft rotor formula. The level energies reproduced are in excellent agreement with experimental values. The magnitude of softness parameter (σ) is observed to decrease with increasing mass number. The nuclear matter does not rotate like classical rotor and moment inertia is observed to be far less than rigid rotor value. The reduction in moment of inertia is attributed to nuclear forces and paring correlations. In nutshell, the 2+ 0+ transition energy is repertoire of vast nuclear information.