Influence of collectivity on reduced hindrance factor of k-isomers in tantalum and hafnium isotopes

The correlations of the reduced hindrance factor F-nu of the K-isomers in Ta and Hf isotopes with respect to NpNn (the product of valence nucle-ons), E-K - E-R (the isomer excitation energy referred to a rigid rotor), and E-K(N-n)-E-K(Nn-max) (the energy difference between the same configura-tion at Nn and Nn-max (middle of a shell), at given spin and isotopic chain) have been re-examined. The analysis is performed in the valence regions divided into particle-particle (p-p), particle-hole (p-h), and hole-hole (h- h) regions, based on the NpNn phenomenology. The Ta and Hf isotopes are considered, given the availability of the same spin configuration in the different sectors of the valence regions. In our study, we observe that the parameter E-K(N-n) - E-K(Nn-max) shows a significant correlation with F-nu, within an isotopic chain.