Separability of compound-nucleus and fragment properties in fission

equilibrium processes still pose a severe challenge to their theoretical description; thus, the realistic modelling of the fission process is far from being achieved at present times. This is a particular problem at low excitation energies, where the influence of nuclear structure is responsible for individual features, which are specific for each fissionning system. Thus, it is important to study a great variety of systems and to measure as many quantities as possible in order to gain a complete overview on the underlying physics. We have analyzed the large body of experimental data on nuclear fission with a semiempirical ordering scheme based on the macroscopic-microscopic approach and the separability of compound-nucleus (CN) and fragment properties on the fission path [1]. Using this approach we analyse [1] the microscopic corrections to the macroscopic potential from the appearance of fission channels. We applied this procedure to 226 Th, 239 U, 252 Cf, and 260 Md as shown in Fig. 1. According to the separability principle [1] it should be possible to trace the microscopic structures deduced in Fig. 1 back to shells in the fragments, which should be the same for all systems. The success of this approach is illustrated in Fig. 1–third row in a schematic way. Obviously, the complex behaviour of shell structure as a function of mass asymmetry of the