Fission-fragment and neutron data traced back to the macroscopic and microscopic properties of the fissioning systems

A new model description of fission-fragment yields and prompt neutron emission is developed. The yields of the different fission channels and their properties are attributed to the number of relevant states above the potential-energy landscape on the fission path at the moment of dynamical freeze-out, which is specific to the collective coordinate considered. The model combines well established ideas with novel concepts. The model is based on the microscopic-macroscopic approach and the separability principle. The separability principle of macroscopic properties of the compound nucleus and microscopic properties of the fragments strongly reduces the number of model parameters and assures a high predictive power. The recently discovered energy-sorting mechanism in superfluid nuclear dynamics determines the sharing of intrinsic excitation energy at scission and the enhancement of even-odd structure in asymmetric splits. We have compared the results of our code with experimental data for a wide range of nuclei ranging from protactinium to fermium isotopes. We considered a broad excitation energy domain going from spontaneous fission to fission induced by 14.7 MeV neutrons. The results of our model for fission fragment mass and charge distributions and for neutron multiplicities agree rather well with the experimental data