重离子碰撞中熔合位垒的研究
Fusion Barriers in Heavy Ion Collisions
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摘要: 熔合位垒的研究对熔合反应以及超重核合成有重要的意义。在改进的同位旋相关的量子分子动力学(ImIQMD) 模型框架下，提取了熔合反应体系40Ca+40Ca，48Ca+208Pb，48Ca+204Pb 和16O +154Sm的熔合位垒。研究了壳修正能对熔合位垒的影响、动力学位垒的能量依赖性、同位旋效应以及形变核的方向效应。计算发现壳修正能降低了熔合反应的位垒。在研究动力学位垒的能量依赖性时，发现位垒高度和位垒半径表现出相反的能量依赖行为。在动力学反应中，当两个核距离接近时，缺中子体系的库仑势同样表现出一定的能量依赖性。对于丰中子体系，由于中子屏蔽作用，库仑势基本没有能量依赖性。Study of fusion barrier is very important for people to better understand fusion reactions. In this paper the Improved Isospin-dependent Quantum Molecular Dynamics(ImIQMD) model is introduced firstly.Then the shell correction effects, energy dependence, isospin effects and orientation effects of fusion barrier are studied. The fusion barriers for the fusion reactions 40Ca+40Ca, 48Ca+208Pb, 48Ca+204Pb and 16O+154Sm are extracted. The negative shell correction energies lower potential barriers of a certain reaction. A complex phenomenon of energy dependence is observed. It is also found that incident energy dependence of the barrier radius and barrier height shows opposite behaviors. The Coulomb potential shows weak energy dependence when distance of two colliding nuclei is lower than the touching distance. The isospin effects of the potential barrier are investigated. The orientation effects of the potential barrier are also discussed for the system 16O+154Sm.Abstract: Study of fusion barrier is very important for people to better understand fusion reactions. In this paper the Improved Isospin-dependent Quantum Molecular Dynamics(ImIQMD) model is introduced firstly.Then the shell correction effects, energy dependence, isospin effects and orientation effects of fusion barrier are studied. The fusion barriers for the fusion reactions 40Ca+40Ca, 48Ca+208Pb, 48Ca+204Pb and 16O+154Sm are extracted. The negative shell correction energies lower potential barriers of a certain reaction. A complex phenomenon of energy dependence is observed. It is also found that incident energy dependence of the barrier radius and barrier height shows opposite behaviors. The Coulomb potential shows weak energy dependence when distance of two colliding nuclei is lower than the touching distance. The isospin effects of the potential barrier are investigated. The orientation effects of the potential barrier are also discussed for the system 16O+154Sm.
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