轴对称奇A核系统的强耦合临界点对称性

鉴于临界点对称性方法在描述原子核形状相变中的成功应用,在强耦合方案下对原有描述偶偶核球形到长椭形状相变的临界点对称性模型X（n）（n=3,4,5）进行扩展,据此建立描述轴对称奇A核系统的SX（n）临界点对称性。通过对X（n）模型与SX（n）模型的转动谱结构进行对比分析,揭示了SX（n）临界点模型的动力学结构受模型维数n的影响较小且更接近刚性转子的模型特征,这些模型特征进一步通过检验过渡区核素150,151,152,153Sm以及172,173,174,175Os中的相关转动带结构得到了初步证实。In view of the successful application of the methods based on critical point symmetries (CPSs) in nuclear shape phase transitions, the new CPSs named SX(n) are established in this work for axially-symmetric odd-A nuclei through extending the original X(n) CPSs with n=3,4,5, which were used to describe the spherical to prolate shape phase transitions in even-even nuclei, in the strong-coupling scheme. By comparing the spectral structures in between the X(n) and the SX(n) CPSs, it is revealed that the dynamical structures of SX(n) are closer to the rigid rotor and less changed with the model dimension in comparison with X(n). Moreover, these features of SX(n) are preliminarily verified by checking the rotational structures of 150,151,152,153Sm and 172,173,174,175Os nuclei.     

Effects of single particle on shape phase transitions and phase coexistence in odd-even nuclei

A classical analysis of shape phase transitions and phase coexistence in odd-even nuclei has been performed in the framework of the interacting boson-fermion model. The results indicate that the effects of a single particle may influence different types of transitions in different ways. Especially, it is revealed that phase coexistence can clearly emerge in the critical region and thus be taken as a indicator of the shape phase transitions in odd-even nuclei.