Dynamical analysis on heavy-ion fusion reactions near Coulomb barrier

TL;DR

This paper introduces an improved quantum molecular dynamics model incorporating shell correction to analyze heavy-ion fusion reactions near the Coulomb barrier, revealing effects of shell structure and nucleon transfer on fusion cross sections.

Contribution

The study develops an enhanced ImIQMD model with shell correction, providing systematic analysis of fusion barriers and cross sections near the Coulomb barrier.

Findings

Fusion cross sections increase for neutron-rich systems.

Shell effects decrease sub-barrier fusion cross sections.

Lowering dynamical barriers enhances sub-barrier fusion.

Abstract

The shell correction is proposed in the improved isospin dependent quantum molecular dynamics (ImIQMD) model, which plays an important role in heavy-ion fusion reactions near Coulomb barrier. By using the ImIQMD model, the static and dynamical fusion barriers, dynamical barrier distribution in the fusion reactions are analyzed systematically. The fusion and capture excitation functions for a series of reaction systems are calculated and compared with experimental data. It is found that the fusion cross sections for neutron-rich systems increase obviously, and the strong shell effects of two colliding nuclei result in a decrease of the fusion cross sections at the sub-barrier energies. The lowering of the dynamical fusion barriers favors the enhancement of the sub-barrier fusion cross sections, which is related to the nucleon transfer and the neck formation in the fusion reactions.