Research On Nuclear Structure In Reflection Asymmetry Relativistic Mean Field Theory

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.