原子核晕结构的研究进展.doc

专业资料专业专心专注毕业设计( 论文) 题目名称:原子核晕结构研究进展学院名称:理学院班级:物理 081 学号: 200800124127 学生姓名:李丰阳指导教师: 王庭太 2012 年6月专业资料专业专心专注原子核晕结构研究进展 Nuclear halo structure research progress 院系名称:理学院班级:物理 081 学号: 200800124127 学生姓名:李丰阳指导教师:王庭太 2012 年6月论文编号: 200800124127 专业资料专业专心专注摘要本文主要讲述了任中洲等人的相对论平均场( RMF ) 模型, 通过大量的查找资料了解了锂,铍, 硼等原子核的中子晕现象和质子晕现象。中子晕现象是上个世纪的重要的物理发现之一, 在此之前, 科学界普遍所持有的一种观点是: 原子核是一种十分紧凑的强束缚的结构, 核的半径正比于质量数的 1/3 次幂, 中子与质子的密度分布具有近似的形状。中子晕的发现, 打破了这一观点, 通过查找的文献可以了解, 一些特殊核的中子密度分布十分弥散, 呈现出异常大的中子均方半径。比如 Arai K 等的实验上发现 11 Li 的中子均方半径竟然接近于 206pb 的中子均方半径。由 Serot 和 Walecka 提出的相对论平均场理论( RMF ) 被广泛地应用, 成功地描述了许多核物质的基本性质: 结合能, 物质电荷半径, 双幻球形核的密度分布等, 均与电子散射实验数据吻合, 使其更精确的计算锂等原子核的基态性质, 研究中子晕和质子晕等现象。关键字: 中子晕,质子晕,相对平均场理论模型专业资料专业专心专注 Abstract In this thesis we mainly investigate the existence of neutron halo Li, Be, B, etc and proton halo in S, P, bya modified Relativistic Mean Field Theory (RMF) model . Neutron halo is one of the most important discovery in late century. Before this discovery, the scientists believed that:all nuclei have strongly binding structure, the radii of the nuclei are proportional to A1/3, and the proton ’s density distribution is similar to the neutron. The discovery of neutron halo broke this old rule, the experiments show that, some special nuclei have extraordinary large neutron RMS(Root Mean Square Radii), displaying a long tail in the density distribution mean field theory has been used in recent years bya number of authors and detailed reviews have been given by Serot and Walecka. This method has turned out to bea very essful tool for the description of many nuclear properties:Binding energies and nuclear charge radii are reproduced to within a few percent and the density distribution of doubly magic spherical nuclei are in excellent agreement with electron scattering data. In this thesis, we reconstruct the RMF model and investigate the basic properties of some nuclei, like 11 Li, 206Pb, in particular the properties of the light halo nuclei. Keyword: Neutron