The Symmetry Axis Orientation And Nuclear-nuclear Interaction Potential Of Heavy Ions In Collisions

In order to arrive at the super-heavy island predicted by nuclear shell model, the synthesis of super heavy elements(SHEs) is becoming an important field in nuclear physics in recent decades. The most important way to synthesize SHEs is the heavy ion fusion reaction where an intermediate mass nucleus is used to bombard a heavy nucleus to obtain the compound nucleus. Because of the developments in theoretical aspect and the demand of experimental aspect, several theoretical models that describe the process of heavy ion fusion reaction have been proposed. Theoretically it is very important to study the reaction mechanism of fusion reactions. The nuclear deformation and nuclear-nuclear interaction potential are two important issues in the study of the mechanism of heavy-ion reactions. Since the nuclear orientation can affect the probability of compound nucleus, the study of evolution of orientation will be very important to the study the fusion reaction. In addition, nuclear deformation can influence the nuclear-nuclear interaction potential significantly, it is of vital importance to study the influence of deformations on the interaction potential. In this thesis, quantum molecular dynamics(QMD) model is used to study the evolution of nuclear orientations and the influence of deformations on the interaction potential.Firstly, the evolution of nuclear orientation for the projectile and target when they are approaching to each other is investigated. The evolution of orientation of the deformed projectile and target at different incident energies and different impact parameter is studied. The results show that the probability that projectile and target rotate to each other is quite large. And with greater impact parameter, the angle of rotation is greater. Furthermore, at the same impact parameter, the higher the incident energy is, the smaller the rotational angle is.Secondly, the static nuclear-nuclear interaction potential is studied. To form the same compound nucleus, the more asymmetric the projectile-target system is, the smaller the static nuclear-nuclear interaction potential is. In addition, we investigate the static nuclear interaction potential at different nuclear orientations. It is found that in tip-tip mode(or tip-sphere, sphere-tip mode), the Coulomb barrier is small and the quasi-fission barrier is large. However, the Coulomb barrier is large and the quasi-fission barrier is small in belly-belly mode( or belly-sphere, sphere-belly mode).