【作者】 圣宗强；

【导师】 郭建友；

【作者基本信息】 安徽大学 ， 理论物理， 2005， 硕士

【摘要】 本文首先详细介绍了相对论平均场理论的一些公式推导,给出了常用的一般的相对论平均场（RMF）的拉格朗日量,从这个拉氏量出发,利用Euler-Lagrange方程就可导出核子与介子场的运动方程。接下来讨论了相对论平均场理论分别对球形核和轴对称形变核的描述和应用。 在对球形核的讨论中,主要研究了晕现象,晕现象是一种普遍现象,它的主要特征是有弱束缚的价重子以及大的物质半径等。形成晕结构的必要条件是:弱束缚、低轨道角动量和短程相互作用。在远离β稳定线的核素的基态和一些稳定核的激发态都可以产生晕现象。相对论平均场理论能成功地重复出实验上观测到的一些晕现象和对某些晕核的预言。对于奇特核中的丰中（质）子晕,选择了²⁸S和⁴⁵S计算,结果表明指出²⁸S可能存在一个双质子晕,⁴⁵S可能存在一个单中子晕。对于激发态中的晕现象,选择了¹⁷O、¹⁷F、⁶⁹Ni和⁷⁰Ni进行计算,结果表明¹⁷O的第一激发态存在一个单中子晕,¹⁷F的第一激发态存在一个单质子晕,而在⁶⁹Ni的第一和第二激发态存在一个单中子晕,在⁷⁰Ni的第一和第二激发态存在双中子晕。 在对形变核的讨论中,用形变的RMF程序对一些轻核区的核素的基态性质进行了描述,结合能的理论和实验数据符合得比较好。并进一步指出了这些元素的单中子滴线和双中子滴线的位置。最后我们还用带形变约束的RMF程序对稀土区的原子核进行了研究,预言了^148～150Nd、^150～152Gd和^152～154Dy这些核中可能存在关键点核。更多还原

【Abstract】 At first, we introduce in detail relativistic mean-field (RMF) theory, where a common Lagrangian density is presented. Starting with this Lagrangian density, we can obtain the Dirac equation and Klein-Gordon equations for nucleon and meson field by using Euler-Lagrangian equation. Next we discuss the application of the RMF theory for the spherical and the axially symmetric deformed nuclei.For the spherical shape nuclei, we mainly study the phenomenon of halo. Halo is very common. The main characters of halo are that the valence nucleons are weekly bound and there are large matter root-mean-square radii of nuclei. The necessary conditions of the formation of halo are: weekly bound, low orbit angular momentum and short distance interaction. Halos can appear in both the ground states of the nuclei far from β-stability line and the excited states of the steady nuclei. The RMF theorycan reproduce the halos, observed in experiment and predict some halo nuclei. For halos in the ground states, 28S and 45S are choused as examples, two-proton halo in 28S and one-neutron halo in 45S are suggested. For halos in the excited states, we choose 17O, 17F, 69Ni and 70Ni as examples, one-neutron halo in 17O and one-proton halo in 17F are suggested in their first excited states. For 69,70Ni, halo structures are suggestedin both the first excited states and the second excited states of 69,70Ni.For the deformed nuclei, we study the nuclear ground state properties in light nuclei region by using the deformed RMF theory. The calculated binding energies are in good agreement with experimental data. We also point out the localities of the single-neutron drip-line and the double-neutron drip-line nuclei. In the end, we study the critical point nuclei in the rare-earth region with relativistic mean field theory, the critical point nuclei are suggested to be 148Nd and 150Nd for Nd isotopes, while 148Nd is the best candidate and 150Nd is slightly to the rotor side of the phase transition. For Gd and Dy isotopes, the critical point nuclei are suggested to be 150,152Gd and 152,154Dy respectively.更多还原