重离子熔合反应系统中的准裂变(英文)

在重离子熔合反应中，准裂变与熔合过程之间相互竞争。在双核模型中，常常在主方程中加入Kramers公式来描述准裂变。但只有当准裂变位垒足够高时，该公式才能成立。在本工作中，把弹靶核的间距作为独立的动力学变量，通过求解主方程来自洽地同时描述双核模型向全熔合和准裂变过程的演化，因此检验了Kramers 公式的适用条件。此外，在重离子熔合反应过程中，把动力学形变的演化和核子的转移过程都看成是耗散过程，在系统的势能面的约束下，同时求解含有动力学形变参量和质量不对称度参量的一系列主方程。研究显示了动力学形变对准裂变质量分布的直接影响，得到了与实验观测值符合得很好的计算结果。In heavy ion fusion reactions, the quasifission(QF) is competing with fusion, and which is often described by incorporating the Kramers formula(KRA-F) into the master equation(ME) within the Di-Nuclear System(DNS) model. However the KRA-F works well only if the QF barrier is high enough. Presently by takingthe relative distance of nuclei as an independent dynamical variable, the evolution of the DNS towards fusion and QF are both treated as a diffusion process in a consistent way by solving MEs. The validity of the KRA-F is thuschecked. Furthermore, the dynamical deformation and the nucleon transfer in heavy ion fusion reaction process are viewed simultaneously as a diffusion process, and are treated by solving a set of MEs with the variables of thequadrupole deformation of each nucleus and the mass asymmetry variable in the potential energy surface(PES) of the system. The distinct influence of the dynamical deformation on the QF mass yield distribution is discussed,and the experimental observations can be well reproduced by the calculation.

Quasifission in Heavy Ion Fusing Reaction Systems

In heavy ion fusion reactions, the quasifission(QF) is competing with fusion, and which is often described by incorporating the Kramers formula(KRA-F) into the master equation(ME) within the Di-Nuclear System(DNS) model. However the KRA-F works well only if the QF barrier is high enough. Presently by takingthe relative distance of nuclei as an independent dynamical variable, the evolution of the DNS towards fusion and QF are both treated as a diffusion process in a consistent way by solving MEs. The validity of the KRA-F is thuschecked. Furthermore, the dynamical deformation and the nucleon transfer in heavy ion fusion reaction process are viewed simultaneously as a diffusion process, and are treated by solving a set of MEs with the variables of thequadrupole deformation of each nucleus and the mass asymmetry variable in the potential energy surface(PES) of the system. The distinct influence of the dynamical deformation on the QF mass yield distribution is discussed,and the experimental observations can be well reproduced by the calculation.