节点文献
反射不对称相对论平均场理论对原子核结构的研究
Research on Nuclear Structure in Reflection Asymmetry Relativistic Mean Field Theory
【作者】 黄海；
【导师】 郭建友；
【作者基本信息】 安徽大学 ， 理论物理， 2011， 硕士
【摘要】 本文详细介绍了反射不对称相对论平均场(全称Reflection Asymmetry Relativistic Mean Field,简称RAS-RMF)理论模型,并用RAS-RMF理论研究了原子核的结构与性质。利用RAS-RMF理论系统地研究了226Th和216Th原子核的基态性质,通过改变RAS-RMF理论计算中双中心谐振子基的不对称系数δ3、形变参数δ2、以及基大小参数N,探讨了基参数的变化对计算结果的影响。虽然在RAS-RMF理论模型计算中对双中心谐振子基参数进行了改变,但研究发现某个的特定区间内计算结果总保持不变,且在此稳定的区间内,计算结果与有限力程小液滴模型(FRDM)计算结果以及实验数据相一致。特别是在利用相对论平均场理论模型计算中,通过引入的反射不对称自由度,使计算结果与实验数据更加符合,这充分说明对描述一些具有反射不对称形变的原子核结构方面,RAS-RMF理论模型更具适用性。利用RAS-RMF理论对镧系区附近的偶偶核Xe、Ba、Ce同位素链的基态性质及形变进行了系统研究。结果表明：RAS-RMF理论很好地描述偶偶核Xe、Ba、Ce同位素链的基态性质,计算的结合能、形变参数与已有的实验数据基本吻合。RAS-RMF理论计算获得的原子核质量密度分布清晰地展现出偶偶核Xe、Ba, Ce同位素链的形状演化过程,与计算得到的形变参数变化规律及实验结果相一致。
【Abstract】 In the paper, we have sketched the theoretical framework of the Reflection Asymmetric Relativistic Mean Field (RAS-RMF) theory. The nuclear structure and properties are investigated by RAS-RMF theory.The ground state properties for the nuclei 226Th and 216Th are investigated by RAS-RMF theory, which is calculated by an expansion method with the two-center harmonic oscillator wavefunctions adopted as the basis. The calculated binding energies and deformations are checked to vary with the parameters of basis, which include the reflection asymmetry parameter 83, the deformation parameter 82, and the size of basis N. The results show that there is an interval for every parameter, where the RAS-RMF calculations are stable and almost unchanged with the value of parameter. In the intervals of parameters, the RAS-RMF calculations agree the experiment as well as the Finite-Range small Droplet Model (FRDM) very well. In particular, the introduction of the reflecting asymmetric degree of freedom improves the RMF calculations, and presents a better description for the nuclei possessing reflection asymmetric deformation.We have applied RAS-RMF theory to investigate the properties of ground states and shape evolution for Xe、Ba、Ce Even-even Isotopic chains. The results show that calculated binding energies and deformations are excellently consistent with experimental data. In particular, RAS-RMF theory provides the quality densities which show clearly the shape evolution of these nuclei. This is in accordance with the variation for parameters of deformations and the experimental observation.