Dependence of total kinetic energy of fission fragments on the excitation energy of fissioning systems

We elucidated the reason why average total kinetic energy (TKE) of fission fragments decreases when excitation fissioning systems increases as indicated by experimental data for neutron-induced events. To explore this problem, we used a method based on four-dimensional Langevin equations have developed. calculated TKE $^{236}$U$^{*}$ and $^{240}$Pu$^{*}$ excited above respective barriers, compared results with n + $^{235}$U $^{239}$Pu reactions, respectively. From Langevin-model analysis, found that shape abundant heavy changes from almost spherical low domain to highly prolate high energy, while light does not change noticeably. The "shape" causes an increase distance between charge centers nascent just after scission increases. Accordingly, Coulomb repulsion two which decrease TKE. In manner, fragment function is key issue nuclei other words, washing out shell effects affect decreasing dependence fragments.