Microscopic study of induced fission dynamics of $^{226}$Th with covariant energy density functionals

TL;DR

This study employs a self-consistent relativistic energy density functional framework to analyze the microscopic dynamics of induced fission in $^{226}$Th, providing insights into potential energy surfaces, scission configurations, and fragment distributions.

Contribution

It introduces a detailed microscopic approach combining relativistic mean-field calculations with time-dependent generator coordinate methods to study fission dynamics of $^{226}$Th.

Findings

Static pairing correlations influence fission fragment charge yields.

The model reproduces total kinetic energy distributions consistent with experimental data.

Fission fragment distributions vary with initial excitation energy.

Abstract

Static and dynamic aspects of the fission process of $^{226}$Th are analyzed in a self-consistent framework based on relativistic energy density functionals. Constrained relativistic mean-field (RMF) calculations in the collective space of axially symmetric quadrupole and octupole deformations, based on the energy density functional PC-PK1 and a $\delta$-force pairing, are performed to determine the potential energy surface of the fissioning nucleus, the scission line, the single-nucleon wave functions, energies and occupation probabilities, as functions of deformation parameters. Induced fission dynamics is described using the time-dependent generator coordinate method in the Gaussian overlap approximation. A collective Schr\"odinger equation, determined entirely by the microscopic single-nucleon degrees of freedom, propagates adiabatically in time the initial wave packet built by boosting the ground-state solution of the collective Hamiltonian for $^{226}$Th. The position of the scission line and the microscopic input for the collective Hamiltonian are analyzed as functions of the strength of the pairing interaction. The effect of static pairing correlations on the pre-neutron emission charge yields and total kinetic energy of fission fragments is examined in comparison with available data, and the distribution of fission fragments is analyzed for different values of the initial excitation energy.