The Study Of Neutron-Rich Nuclear Structure In A～100Mass Region

The study of neutron-rich nuclei is one of the current frontier topics in nuclear physics, neutron-rich nuclei in the mass A-100region exhibit many interesting structural phenomena. The research in this mass region started more than four de cades ago when Cheifetz et al. observed a sudden onset of deformation in Zr isotopes, and thereby discovered a new region of nuclei with large, stable deformation. Recently, with the development of experimental techniques, such as Gammasphere and Eurogam, remarkable progress has been made in the investigation of nuclear structure in A-100mass region, so nuclear spectrum information has been greatly enriched in this nuclei region. In addition, the valence nucleons begin to fill the hl1/2neutron and the g9/2proton orbitals, so the properties of these nuclei display a high sensitivity to the number of neutrons and protons, giving rise to interesting variations in structure, for example:a sudden onset of large deformation, shape coexistence, identical bands etc.Performing shell model calculations for heavy nuclei is a long-standing problem in nuclear physics, the shell model truncation in the configuration space is an essential step. The Projected Shell Model (PSM) truncates the space under the guidance of the deformed mean-field solutions, this implies that the PSM suggests a way to bridge the two conventional methods:the deformed mean-field approximations, which are widely applied to heavy nuclei but able to describe the physics only on average in the intrinsic frame, and the spherical shell model diagonalization method, which is most fundamental but feasible only for small systems. Thus, we combine the advantage of the both methods by PSM, which could easily interpret lots of physics phenomenon, Moreover, it could magnificently restore Angular momentum by the projected method, so we may compare theoretical results with experimental data directly, then to explain the experimental results.Based on the advent of new research in A-100mass region above, and to understand the structure of neutron-rich nuclei and to validate the existing theoretical model for the exotic mass region, we have investigated systematically98～101Sr and100～103Zr axial symmetric isotopes by wielding the projected shell model in this article, a series of side bands energy which include the experimental observation and the theoretical prediction were calculated by PSM approach in these nucleus, the investigation indicated the energy levels of ground band and side bands were reproduced well by theoretical calculation, at the same time, the identical transition phenomenon is studied in this regionFirstly, through the further investigation for these nucleons, the known experimental data are reproduced very well and some low-lying side band are predicted, the research indicted the influence of the g9/2proton orbital and hl1/2neutron orbital on the structural properties. For the even-even nuclei, the structure of side bands is described and some properties of the ground band is analyzed in detail. For the odd-neutron isotopes, the discussion is concentrated on the excited single particle configurations. Secondly, transition energies of ground band, kinematic and dynamic moment of inertia were investigated by our PSM calculations in98，100Sr isotopes, The good agreement with the experimental results indicate that the identical transition in ground band in98，100Sr isotopes observed in experimental work was reproduced well by the theoretical calculation, which could confirm the identical bands emergence in low spin region. Moreover, the theoretical moment of inertia deviate from the experimental data, it has been interpreted the deformation parameters are constant. Finally, I hope our predictions would help future experiments with identification of band structures in the very neutron-rich nuclei.