重离子熔合反应系统中的准裂变(英文)  

Quasifission in Heavy Ion Fusing Reaction Systems

作　　者：郁琳[1,2] 甘再国[1] 黄明辉[1] 张鸿飞[3] 李君清[1,3] 

机构地区：[1]中国科学院近代物理研究所,甘肃兰州730000 [2]中国科学院大学,北京100049 [3]兰州大学核科学与技术学院,甘肃兰州730000

出　　处：《原子核物理评论》2013年第3期299-307,共9页Nuclear Physics Review

基　　金：National Natural Science Foundation of China(11120101005,11175074,11105035,10805061,10825522,10975064);Knowledge Innovation Project of Chinese Academy of Sciences(KJCX2-EW-N01);National Basic Research Program of China(973 Program)(2007CB815000)~~

摘　　要：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 taking the 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 thus checked. 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 the quadrupole 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.

关 键 词：超重核 准裂变 熔合 主方程 驱动势 

分 类 号：O571.6[理学—粒子物理与原子核物理]