Calculation And Analysis For Hole-nuclei Near ¹³²Sn By A Large-scale Shell Model

As an important branch of physics, nuclear structure theory is a front applied discipline. Considering shell effect and magic number in nuclear structure, the shell model what beginning with independent particle approximation obtains single particle energy by mean field, then adding two body residual interaction to mix configurations.After considering the spin-orbit coupling, the magic number is explained perfectly that establishes the fundamental position of shell-model theory in nuclear structure.For shell model calculation, Selecting properly model space is the first step. The model space should be enough to contain physics and also should be suit to the computing power. It may be a major shell, or several orbits covering valence nucleons.The initial shape of the model space is determined by the single particle energy corresponding to every orbit, which decided by both the binding energy and low excited states of the single particle nucleus lying in the selected model space.When the model space and single particle energy is ready, a suitable Hamiltonian is needed that shows the interaction between particles inner nucleus. Considering the nuclear force is very complex, there is no good Hamiltonian that comes from nuclear scattering experiment with asymmetry and saturability. Instead, it takes self-consistent Hamiltonian. For shell-model calculation, the Nushell X code is one of the common calculating program, which can calculates many nuclear structure properties. For example, the energy level, the wave function, gamma and beta decay and so on.In the present work, firstly the EPQQM model from professor Hasegawa and Kaneko is used to the hole-nuclei near132 Sn. Not only obtaining the self-consistent Hamiltonian, but the energy spectrum and isomer are explained successfully. For example,the isotopes 127-131 Sn, the isotopes 128-131 In, and also the nuclei 130 Cd, 128 Pd and126Pd. Furthermore, the electromagnetic transitions in130 Cd,128Pd and126 Mo,as well as the persistence of the N =82 shell closure in the neutron-rich132 Sn region are analyzed. The 8+level in126 Ru will be a nice senior isomer as theory prediction.Both theory and experiment show that the N =82 shell in excess neutron region is robust enough. Which will not only influences the nuclei property in this nuclei region,but also the heavy elementary synthesis and elemental abundance distribution in the cosmos.