Microscopic analysis of induced nuclear fission dynamics

TL;DR

This paper combines two microscopic quantum methods to analyze low-energy induced nuclear fission dynamics, providing detailed predictions of fission fragment distributions and energies, and comparing the effects of quantum fluctuations and dissipation.

Contribution

It introduces a combined microscopic framework using TDGCM and TDDFT to study fission dynamics, offering new insights into the roles of quantum fluctuations and dissipation.

Findings

Calculated charge distributions and kinetic energies for $^{240}$Pu fission.

Compared effects of quantum fluctuations and dissipation mechanisms.

Validated model predictions against experimental data.

Abstract

The dynamics of low-energy induced fission is explored using a consistent microscopic framework that combines the time-dependent generator coordinate method (TDGCM) and time-dependent nuclear density functional theory (TDDFT). While the former presents a fully quantum mechanical approach that describes the entire fission process as an adiabatic evolution of collective degrees of freedom, the latter models the dissipative dynamics of the final stage of fission by propagating the nucleons independently toward scission and beyond. By combining the two methods, based on the same nuclear energy density functional and pairing interaction, we perform an illustrative calculation of the charge distribution of yields and total kinetic energy for induced fission of $^{240}$Pu. For the saddle-to-scission phase a set of initial points for the TDDFT evolution is selected along an iso-energy curve beyond the outer fission barrier on the deformation energy surface, and the TDGCM is used to calculate the probability that the collective wave function reaches these points at different times. Fission observables are computed with both methods and compared with available data. The relative merits of including quantum fluctuations (TDGCM) and the one-body dissipation mechanism (TDDFT) are discussed.