Level Density and Fission Probability in Spherical and Deformed Nuclei

摘要

The important role of rotational increase in the level density of nuclei in a description of the observed fission probability of sub-actinide nuclei is demonstrated. From an analysis of the experimental data available there is found for the corresponding coefficient an energy dependence that exhibits deviations from the adiabatic estimate of rotational effects in highly excited nuclei. By allowing for collective effects in fission and neutron decay channels of compound nuclei, it is possible to obtain a consistent description of the fissionability observed both in the near-threshold region and in the high-energy region, where fission by means of emission is dominant. The dependence of fission barriers on mass number, as determined from an analysis of the fissionability of sub-actinide nuclei, differs considerably from what was found in previous work. 10 figures. (ERA citation 06:004345)