# Time-dependent generator coordinate method study of mass-asymmetric fission of actinides

## TL;DR

This paper develops a unified theoretical framework using the generator coordinate method to study the fission dynamics and charge distributions of actinide nuclei, achieving results that align well with experimental data.

## Contribution

It introduces a time-dependent GCM approach with finite-temperature effects to accurately model actinide fission fragment distributions.

## Key findings

- Charge yields for specific actinides match experimental data.
- Predicted mass asymmetry aligns with shell-stabilized octupole deformation studies.
- The model effectively captures low-lying collective states and fission dynamics.

## Abstract

Low-energy positive and negative parity collective states in the equilibrium minimum, and the dynamics of induced fission of actinide nuclei are investigated in a unified theoretical framework based on the generator coordinate method (GCM) with the Gaussian overlap approximation (GOA). The collective potential and inertia tensor, both at zero and finite temperature, are computed using the self-consistent multidimensionally constrained relativistic mean field (MDC-RMF) model, based on the energy density functional DD-PC1. Pairing correlations are treated in the BCS approximation with a separable pairing force of finite range. A collective quadrupole-octupole Hamiltonian characterized by zero-temperature axially-symmetric deformation energy surface and perturbative cranking inertia tensor, is used to model the low-lying excitation spectrum. The fission fragment charge distributions are obtained by propagating the initial collective states in time with the time-dependent GCM+GOA that uses the same quadrupole-octupole Hamiltonian, but with the collective potential and inertia tensor computed at finite temperature. The illustrative charge yields of $^{228}$Th, $^{234}$U, $^{240}$Pu, $^{244}$Cm, and $^{250}$Cf are in very good agreement with experiment, and the predicted mass asymmetry is consistent with the result of a recent microscopic study that has attributed the distribution (peak) of the heavier-fragment nuclei to shell-stabilized octupole deformations.