Study On Multi-nucleon Transfer Reaction By Quantum Molecular Dynamics Model

The production of new neutron-rich nuclei is one of the hot field in nuclear physics recently and the multi-nucleon transfer reaction is an important method to produce neutron-rich nuclei.In this thesis,the quantum molecular dynamics?QMD?model was used to study the multi-nucleon transfer reaction.The thesis can be divided into three parts.In the first part:the QMD model and the improved QMD?ImQMD?model are introduced.The cutoff condition of final state in ImQMD model was improved.The statistical decay model GEMINI++is adopted after the collision reaction stage and the model was also introduced.The second part:The kinetics of multi-nucleon transfer reaction in ¹³²Sn+²⁰⁸Pb system was studied by using ImQMD model.We calculated the total kinetic energy loss?TKEL?of the reaction at different energies and impact parameters.The results show that TKEL is strongly dependent on the incident energy and TKEL increases with increasing the incident energy.The effects of the incident energy and the impact parameters on the number of transferred nucleons in multi-nucleon transfer reactions were also investigated.Finally,we studied the angular distribution of the product.The angular distributions in the center of mass and the laboratory frames were calculated,respectively.The third part:Firstly,we studied the effect of impact parameters on product distribution.Secondly,the isotopic distributions for some nuclides were investigated.The product distribution of primary fragments was compared with that of secondary fragments.The isotopic product distribution with charge number 72<Z<77 was compared with the results of DNS?di-nuclear system?model calculation.We extracted the nuclide distribution for the neutron number N=126 and compared the results with those of other theoretical models.The results show that some undiscovered neutron-rich nuclei have larger cross sections???0.1mb?in the product distribution of N=126.The results could be useful for experimental investigations.Finally,the range of impact parameters for edge collision reaction was estimated and the results of ImQMD were compared with those of GRAZING model.