Research on excitation mechanism for medium and heavy nuclei via approaches beyond mean field approximations

我们用各种模型研究了中、重核的核结构，得到了以下结果：(1)用四极耦合模型研究了质量为130左右的双奇核的双重带。通过对波函数的分析，我们发现这些态的能级格式是由未配对中子和未配对质子的两个角动量的筷子组态产生的，它们与偶偶核的四极激发弱耦合。(2)对富含中子的Se、As、Ge和Ga同位素进行了壳层模型计算，并将计算的能级和电磁跃迁与实验数据进行了比较。通过对壳层模型结果的分析，证实了在高自旋下，0g_<9/2>轨道上两个中子的自旋排列是明显的。(3)为了研究跃迁核的结构，我们提出了一种新的发电机坐标法计算算法。将该模型应用于均匀的Se和Ge核，表明了质量80区的三轴变形的重要性。

We have studied the nuclear structure of medium and heavy nuclei in terms of various models and have obtained the following results. (1) We investigated the doublet bands in the doubly-odd nuclei around the mass 130 in terms of the quadrupole coupling model. By analyzing wave functions, we have found that the level scheme of these states arises from chopsticks configurations of two angular momenta of the unpaired neutron and the unpaired proton, weakly coupled with the quadrupole excitations of the even-even core. (2) We performed shell-model calculations for neutron-rich Se, As, Ge, and Ga isotopes, and compared the calculated energy levels and electromagnetic transitions with the experimental data. Through the analysis of the shell model results, it is confirmed that the spin alignment of two neutrons in the 0g_<9/2> orbital becomes apparent at high spins. (3) We have developed a new algorithm for generator coordinate method calculations in order to investigate the structure in transitional nuclei. An application of this model to the even-even Se and Ge nuclei indicated the importance of triaxial deformation in the mass 80 region.