Dynamics of dinuclear system formation and its decay in heavy ion collisions

TL;DR

This paper investigates the formation and decay of dinuclear systems in heavy ion collisions at low energies, analyzing experimental data with a model to understand reaction mechanisms and factors affecting residue yields.

Contribution

It applies the dinuclear system model to interpret experimental data, providing detailed insights into fusion hindrance, quasifission, and survival probabilities in heavy ion collisions.

Findings

Small evaporation residue cross sections explained by fusion hindrance and instability.

Fusion hindrance due to competition between fusion and quasifission.

Survival probability decreases with excitation energy and angular momentum.

Abstract

A variety of phenomena connected with the formation of a dinuclear complex is observed in the heavy ion collisions at low energies. The dinuclear system model allows us to analyze the experimental data and to interpret them by comparison of the partial capture, fusion and evaporation residue cross sections measured for the different reactions leading to the same compound nucleus. The comparison of theoretical and experimental values of the mass and angular distributions of the reaction products gives us a detailed information about reaction mechanism forming the observed yields. The observed very small cross sections of the evaporation residues may be explained by the strong fusion hindrance and/or instability of the heated and rotating compound nucleus and smallness of its survival probability. The fusion hindrance arises due to competition between complete fusion and quasifission while the smallness of survival probability is connected with the decrease of the fission barrier at large excitation energy and angular momentum of compound nucleus.