Experimental Extraction And Isospin Effects Of Fusion Barriers In Heavy-ion Fusion Reactions

Heavy-ion fusion reactions is not only an important way to study the nuclear structure effects,dynamics effects and nuclear interaction,but also is quite helpful for the synthesis of super-heavy nuclei.The fusion barriers have close relations with fusion mechanism in heavy-ion fusion reactions.Fusion reactions induced by neutron-rich nuclei play a vital role in the study of nuclear structure and nuclear astrophysics.In this paper,the fusion excitation functions of 60 reactions are systematically studied,the main works and the findings include:Firstly,a method is proposed to improve linear fitting for extracting fusion barriers height.Extracting and analyzing the fusion barriers height with a linear fitting and differential method based on the directly measured fusion excitation functions.It is found that the results from the two methods are very close to each other,and the root mean square deviation with respect to 60 reactions is 0.25 MeV.Secondly,the regulation of the fusion barrier height changing with the neutron number of the target is studied,which based on the extracted fusion barrier height.The results show that the barrier height decreases systematically with the increase of the neutron number in the reaction partner for the system with weak shell effects.The situation is more complicated for systems with strong shell effects,which implies that the shell effects and the isospin effects compete with each other.Finally,we study systematically the entrance channel nucleus-nucleus potential of32,36 S +90,91,92,94,96,98,100,102,104 Zr and16,18 O +90,91,92,94,96,98,100,102,104 Zr based on the Skyrme energy-density functional.It is found that the barrier height decreases linearly with the increase of neutron skin thickness,which is consistent with the experimental data.It shows that if shell effects is not taken into account,the isospin effects will reduce the barrier height with the increase of the number of neutrons.