The Neutron-rich Nuclei Ru And Neutron-deficient Nucleus Ba Even-even Isotopes By Projected Shell Model

Nuclear is an important level of substance structure, so the study of its structure and properties is particularly important, but because the nucleus itself is a complex quantum many-body system, on the micro level, it is difficult to accurately solve its structural characteristics, only can we rely on approximate ways to give the description of the nucleus to be studied, so various phenomenological models are proposed to explain and predict some experimental phenomena on nuclear structure characteristics. Among these nuclear structure models, projected shell model, as one of the more successful models has been used widely, and gradually extended and improved.Currently in the study of nuclei, nuclear of A～100transition region and A～130rare earth transition area is a hot issue of nuclear research, the former contain nuclear from Z=38,40large deformation region then triaxial deformation one to the spherical shell Z=50transition region, the structural features of which are rich and complex. The latter focused on a number of cutting-edge study in high-spin states, such that the shape-driving effect of the high spin states has been the focus of attention., the theory predicts that the district has Y soft-core, high-j intruded tracks of quasi-particle have obvious impact on the nuclear shapes,for instance, they lead to the transformation of prolate spheroidal and oblate spheroidal deformation of nuclear, and even the so-called shape coexistence phenomenon. In this paper, projected shell model is used to study even-even nuclei isotopes of the neutron-rich nuclei and neutron-deficient nucleus for the two nuclear areas, the results indicate that Ru isotopes may have prolate shapes, and with the increase in the number of neutrons, the changes of deformation values are not obvious, but the moment of inertia of112Ru nuclear speed up with spin in figure of moment of inertia, which shows a certain soft deformation characteristic for112Ru, consistent with experimental data, and also foreshadowed as other theory that there may be an transformation of significant prolate deformation to significant triaxial deformation in these three isotopes with increase of neutron number. and explained the observed back bending phenomenon of the moment of inertia of yrast band for these three nuclear, its essence is two quasi-neutron band cross with the base band, which is due to the alignation of quasi-neutron angular momentum along the axis of rotation, and the second back bending of the last two isotopes are due to a pair of protons aligned angular momentum. Similarly, the results for Ba isotopes indicate that these three nuclear may have prolate shapes and deformation values decrease with increasing neutron number, or there is a trend of deformation transition from prolate deformation to triaxial deformation, which can be inferred from the variation feature of the moment of inertia of yrast band obtained from theoretical and experimental results, and that is to say130Ba has a soft features of triaxial deformation, this result is consistent with the ones from some other theoretical predictions Also we explain that the observed back bending phenomenon of yrast band of these three isotopes may be attributed to the angular momentum alignment a pair of protons. In this paper we verifies the applicability of projected shell model for neutron-rich nuclei108,110,112Ru and neutron-deficient nuclei126,128,130Ba isotopes, and demonstrates the strong ability of the model to describe and predicte the structure properties of nucleus.