40,48Ca+90,96Zr融合反应的动力学模型研究

应用改进的量子分子动力学模型,在严格挑选初始核考虑弹靶结构效应的基础上,研究了近垒和垒上融合反应^40,48Ca+^90,96Zr. 研究表明: 4个反应的理论计算截面与实验值很好符合; 丰中子反应⁴⁰Ca+⁹⁶Zr的垒下融合截面比其他3个反应有明显增强的现象.为了理解丰中子反应⁴⁰Ca+⁹⁶Zr与⁴⁰Ca+⁹⁰Zr相比垒下融合截面增强,而Ca+⁹⁶Zr垒下融合截面没有明显增强的原因, 进一步分析了484个反应的融合位垒,中子转移与融合位垒的关系、中子转移与Q值的关系,结果表明: 正反应Q值会引起核子(特别是中子)转移的增强,从而导致动力学融合位垒的下降和垒下融合截面增强.

Dynamic Model Study of Fusion Reactions for 40,48Ca+90,96Zr

Based on the Improved Quantum Molecular Dynamics Model the fusion reactions of 40,48Ca 90,96Zr are studied by making a more rigorous treatment of the initial condition. The study shows that: (1) the calculated fusion cross sections for all four reactions of 40,48Ca 90,96Zr are in good agreement with experiment data; (2) the sub-barrier fusion for the neutron-rich reaction 40Ca 96Zr is substantially enhanced as compared with the other three reactions. In order to understand the reason why the sub-barrier fusion of the neutron-rich reaction 40Ca 96Zr is enhanced as compared with the non-neutron-rich reaction 40Ca 96Zr and that of the neutron-rich reaction 48Ca 96Zr is not enhanced, the further investigations are carried out, those are: the dynamic fusion barriers for four reactions, the relation between dynamic fusion barrier and nucleon transfer and the relation between nucleon transfer and corresponding reaction Q value. It has been found that positive Q value leads to the strong nucleon transfer which reduces the dynamic fusion barrier and enhances the sub-barrier fusion cross section.