Modelling the widths of fission observables in GEF

Abstract

Abstract. The widths of the mass distributions of the different fission channels are traced back to the probability distributions of the corresponding quantum oscillators that are coupled to the heat bath, which is formed by the intrinsic degrees of freedom of the fissioning system under the influence of pairing correlations and shell effects. Following conclusion from stochastic calculations of Adeev and Pashkevich, an early freezing due to dynamical effects is assumed. It is shown that the mass width of the fission channels in low-energy fission is strongly influenced by the zero-point motion of the corresponding quantum oscillator. The observed variation of the mass widths of the asymmetric fission channels with excitation energy is attributed to the energy-dependent properties of the heat bath and not to the population of excited states of the corresponding quantum oscillator.

Nucleosynthesis of heavy elements in the r-process

“…It is possible that, with increasing fissilenucleus mass, the mass distribution of fission products will again become asymmetric, tending to known or some other magic numbers [135,136], and this will affect changes in the mass distribution. In recent years, there appeared alternative calculations of the mass distribution of fission products [73,137,138] both for fragments measured experimentally and for exotic nuclei whose distribution is necessary for describing rapid nucleosynthesis. As a matter of fact, the saddle-point models proposed in [73,137] are modifications to the old models from [139], different parametrizations leading to different versions of one-to four-humped distributions that one applies in simulating the synthesis of heavy elements and which solve partly the problem of smoothing the odd-even effect in the model-dependent abundances of heavy elements in the cases where the rprocess forms cycles because of fission and improve agreement between the results of calculations and observations, but they do not solve the problem of specifying a model that would be the most viable physically.…”