PHENOMENOLOGY OF NUCLEI AT VERY HIGH ANGULAR MOMENTA USING PARAMETRIZED 2-CENTER NUCLEAR SHAPES

The nuclear shapes and variation of moment of inertia with angular mom entum, as well as the limiting angular momentum carried by a nucleus a t its fissioning stage, are derived from the observed data of the grou nd-state yrast band and quadrupole deformations of these states. The n ecking-in of the nuclear shapes are shown to start already at J(pi) si milar to 14(+)-18(+). The empirical variation of moment of inertia wit h angular momentum is found to include the back-bending and forward-be nding effects and supports the nuclear softness model of the nucleus. The fission of nuclei is shown to occur at very high angular momenta, which is different for different nuclei. The role of deformation energ y is analyzed and the possibility of predicting the quadrupole deforma tions, or B(E2) transitions, for very high spin states is discussed. T he calculations are presented for(156)Dy, Er-158, and Hf-164.