核裂变断点动力学的微观理论研究

Nuclear fission is one of the most complex processes in nuclear physics, involving a strong interplay between nuclear structure and dynamics. Despite the huge theoretical effort pursued by several generations of physicists, many crucial facets of this process are still not understood at fundamental level, warranting further exploration of its dynamics. This is more so when viewed from the microscopic theoretical point of view... Scission dynamics of nuclear fission represents one of the most challenging problems in many-body theory as it plays crucial role for determining the main properties of fission fragments and the emitted light particles. With the aid of the advanced energy density functional and by mainly focusing on the scission process, we will microscopically investigate the nuclear fission processes, the multi-dimensional potential energy surface, the configuration of scission point, more importantly, the non-adiabatic dynamics in the course of deformation from saddle to scission and also in post-scission, in order to make clarification on the fission mechanisms, the nature of scission and some other basic problems. Based on the above studies, we will also fully discuss and analyze some characteristic experimental phenomena. .. Through this study, we will try to obtain some physical insights and deep understandings on fission mechanism. We hope to provide theoretical supports to the quantitative calculation of experimental variables and the evaluation of high-precise nuclear data. We also hope to provide valuable references for the studies on the formation of heavier nuclei in astrophysics, searching for the super-heavy elements, design of new generation of accelerator and nuclear reactor, and application of nuclear resources.

核裂变是核物理中最为复杂的过程之一，涉及核结构与动力学的相互关联。尽管经过几代物理学家的不懈努力，裂变过程的许多重要方面仍然没有在最基本的层面上得到理解。.. 核裂变断点动力学过程，是裂变现象中一个十分重要的过程，对确定裂变碎块和出射轻粒子的主要特征起着决定性的作用。本项目中，我们将围绕断点动力学过程，以能量密度泛函理论为基础，从微观上对核裂变位能曲面，断点组态和性质，特别是断点和断后动力学过程进行系统地分析和讨论。就核裂变的动力学机制、以及断裂过程中的一些基本问题作出探索性研究。并对一些有重要意义的实验现象进行分析和理解。.. 通过本项目的研究，希望获得对核裂变机制的系统和清楚理解，为实现裂变可观测量、高质量核数据的计算和评价提供理论上的支持，并对天体重核的形成过程、超重核合成机制研究，新一代加速器和反应堆设计，以及核能利用等提供有价值的参考。

核裂变断点动力学过程，是裂变现象中一个十分重要的过程，对确定裂变碎块和出射轻粒子的主要特征起着决定性的作用。对裂变过程进行系统的理论和实验研究，对于理解裂变机制、揭示低能核动力学的复杂性、检验核多体动力学理论都有着十分重要的意义。.本项目基于Gogny核子-核子有效相互作用, 发展了适用于描写原子核裂变过程、不包含任何对称性限制以及三维时间相关的Hartree-Fock-Bogoliubov理论计算程序(Gogny-TDHFB Code for Fission)。程序包含静态裂变势能面计算的多维度集体自由度约束HFB和裂变动力学计算的TDHFB两部分。对240Pu、230-232Th、180Hg、246，258Fm等核自发裂变的裂变位能面和断点动力学进行系统的计算和分析。所得结果表明, 对能在核裂变过程, 特别是在断裂动力学过程中起着十分重要的作用。.通过本项目的实施，使我们对核裂变机制，特别是对能在核裂变过程中的作用有了更加深入系统的理解。完成了项目各年度计划和总体的工作目标。为今后从动力学上、进一步研究核裂变过程，核熔合过程等各种实际问题打下了坚实的基础。