偶^(80^86)Zr核的形状相变和对相变及其演化  

Shape Transition and Pair Phase Transition Together With Their Evolution on Even ^(80-86)Zr Isotopes

作　　者：倪绍勇[1] 石筑一[1] 

机构地区：[1]贵州民族学院物理系,贵州贵阳550025

出　　处：《原子能科学技术》2004年第6期487-491,共5页Atomic Energy Science and Technology

基　　金：贵州省科技基金资助课题(黔基合计字[2002]3025)

摘　　要：应用唯象核芯+两准粒子模型的一种微观实现(微观sdIBM-2-2q.p.方案)和实验单粒子能量,较成功地再现了偶80-86Zr核的基态带、γ带和部分高自旋态能谱,实现了它们从近SU(3)对称性到O(6)对称性,继而向U(5)对称性过渡的整个形状相变过程。基于唯象模型和微观方案推出s玻色子不拆对的结论,及1个d玻色子发生拆对顺排所需要的最小能量阈值。该阈值明确指认:随着中子空穴数的减少,偶Zr同位素可能发生着从80Zr核的两准质子顺排态向着86Zr核的两准中子顺排态的演化。By using a microscopic sdIBM-2+2q.p. approach which is the accomplishment of the phenomenological core plus two-quasi-particle model and the experimental single-particle energies, the levels of the ground-band, γ-band and partial two-quasi-particle states on even 80-86Zr isotopes are successfully reproduced. The shape transition which transits from SU(3) symmetry to O(6) one, then to U(5) one for the isotopes is achieved. Based on the phenomenological model and microscopic approach, it has been deduced that no s-boson in the nucleus occupies breaking pair and aligning; and the minimum aligned energy required when one d-boson does is obtained. The threshold value explicitly indicates that along with the increase of neutron number, the evolvements from the two-quasi-proton states on 80Zr nucleus to the two-quasi-neutron states on 86Zr nucleus may take place in even Zr isotopes.

关 键 词：形状相变 对相变 锆同位素 原子核 自旋态能谱 

分 类 号：O571.2[理学—粒子物理与原子核物理]