Rotational Invariance in the Centrifugal Stretching of Deformed Nuclei

An explicit model is developed for the rotational and quasi-rotational states of heavy deformed nuclei. It is assumed that the effective mass contributing to the rotational inertia lies outside a central, geometric core which is rotationally invariant. The effective mass is modified as a result of nuclear stretching which is assumed to take place against harmonic restoring forces. Good agreement with experiment is obtained for the so-called hard rotators and even for the neutron deficit and transition nuclei. Explicit expansions are obtained for the energy spectra and the effective moments of inertia in the form of asymptotic series in the angular momentum variable. These series give better convergence for low angular momenta and hard rotators.