Fragment mass distributions of quasifission induced by 238U on 16O,26Mg,32S,35Cl,40Ca and 65Zn targets at several bombarding energies have been calculated with the two-step model.The experimental data are reproduced consistently,and the mechanism of the distribution shape is also analyzed by investigating the diferent incident channels.
Fusion hindrance in the radial degree of freedom for massive nuclear reactions is known for a long time. However the present work shows that the fusion hindrance also exists in the neck evolution. We calculate the potential at different distances and different neck parameters by the two-center liquid drop model and then check whether fusion hindrance exists in the neck evolution by examing the sign of slope of potential vs. the neck parameter. The area of fusion hindrance in the neck evolution is shown.
The nuclear and Coulomb potentials between deformed nuclei with octupole deformations and arbitrary orientations are evaluated numerically.The effects of the octupole deformation on the potential between nuclei and the potential energy surface(PES) used in the description of the production of super-heavy nuclei(SHN) by heavy-ion fusion reactions are investigated in the di-nuclear system model.It is found that the nuclear octupole deformation significantly changes the shape of the PES,which may influence the fusion probability of the SHN.Also,PESs in the tip-belly and belly-belly cases are investigated.Finally,the quasifission barriers in the tip-tip and belly-belly cases are evaluated.It is found that the quasi-fission barriers of the belly-belly case are generally larger than those of the tip-tip case.
