Abstract
Phys. Rev. C 103, 031304 (2021) Energy dependence of fission observables is a key issue for wide nuclear
applications. We studied real-time fission dynamics from low-energy to high
excitations in the compound nucleus $^{240}$Pu with the time-dependent
Hartree-Fock+BCS approach. It is shown that the evolution time of the later
phase of fission towards scission is considerably lengthened at finite
temperature. As the role of dynamical pairing is vanishing at high excitations,
the random transition between single-particle levels around the Fermi surface
to mimic thermal fluctuations is indispensable to drive fission. The obtained
fission yields and total kinetic energies with fluctuations can be divided into
two asymmetric scission channels, namely S1 and S2, which explain well
experimental results, and give microscopic support to the Brosa model. With
increasing fluctuations, S2 channel takes over S1 channel and the spreading
fission observables are obtained.