A quasiparticle-rotor model with variable moments of inertia

A scheme is developed for including the variable-moment-of-inertia (VMI) formalism of even-even nuclei in the particle-rotor model for odd nuclei. Two approaches are considered, a VMI related to the total spin of the odd nucleus and a VMI depending on the spin of the rotating core. The model is applied to sup(149,151,153)Sm and 109Pd. Special emphasis has been given to the problem of the antialigned low-spin states of weakly deformed nuclei. The parametrization gives an excellent account of the aligned members of various bands with widely different shapes in soft nuclei like 149Sm, but still fails to reproduce the energies of antialigned band members. (orig.)