Description of the yrast superdeformed bands in even-even nuclei in A ~ 190 region using the nuclear softness model

A two-parameter nuclear softness (NS2) model for the transition energies is proposed by treating the variation of the moment of inertia with spin. The model has been applied to the yrast superdeformed (SD) bands in even-even nuclei in the mass region A ~ 190. The model parameters have been determined from the fitting procedure in order to minimize the relative root mean square deviation between the experimental E2 transition γ -ray energies and the calculated ones. The basic experimental data on SD bands are given in the form of a series of γ -ray transitional energies and the spins were determined in our previous works. The excellent agreement between the theory and the experiment give good support to the model. The presence of identical bands between the two isotopes 192 Hg and 194 Pb is investigated because their differences in γ -ray energies are small and constant up to rotational frequency ℏω ~ 0.25 MeV. Our analysis also leads to the appearance of ∆ I = 2 staggering effect in 194 Hg (SD1). A comment on equilibrium deformation for each nucleus is also given.