在中能重离子反应中核子的运动特征

Behavior of Individual Nucleon in Intermediate Energy Heavy Ion Reactions

在量子分子动力学模型框架下，研究了在中能重离子反应中单个核子的运动形态是规则的还是混沌的，它与反应系统的整体性质、反应机制是有关联的．在稳定的复合系统中，核子的运动显示出规则的行为．规则行为与混沌行为的并存反映了规则区域被不规则区域所包围的排斥极分岔特性，说明有中等质量碎片的局域稳定源存在．更多的不稳定轨道的出现则标志着这种局域稳定源的减少，有更多的核子及小集团发射．核子的混炖运动比核物质状态方程所标志的力学不稳定区域出现的时间更早．

In the framework of Quantum Molecular Dynamics model the individual nucleon behavior(regular or chaotic)in the intermediate energy heavy ion reactions is investigated.The correlation between the nucleon behavior and the reaction fragmentation mechanism is analysed.The nucleon motion in the evolution process of a compound nuclear system showed regular behavior.The coexistance of the regular trajectories and the chaotic ones suggests that the regular regions in the interaction area embed in irregular ones,reflecting the fractal nature of the repellor,and indicating the existance of local stable potential generated by intermediate mass fragment.The appearance of more instable trajectories associated with the decreasing number of nucleon and small cluster emission.The chaotic nucleon motion began earlier than the time when the system may reach the region of mechanical instability characterized by equation of state of nuclear matter.