超越平均场模型对Ba同位素链八极形状演化研究  

Beyond-mean-field Study of Octupole Shape Evolution in Neutron-deficient Ba Isotopes

作　　者：孙玮 全珊 向剑 李志攀[1] SUN Wei;QUAN Shan;XIANG Jian;LI Zhipan(School of Physical Science and Technology,Southwest University,Chongqing 400715,China;School of Physics and Electronic,Qiannan Normal University for Nationalities,Duyun 558000,Guizhou,China)

机构地区：[1]西南大学物理科学与技术学院,重庆400715 [2]黔南民族师范学院物理与电子科学学院,贵州都匀558000

出　　处：《原子核物理评论》2019年第2期144-150,共7页Nuclear Physics Review

基　　金：国家自然科学基金资助项目(11475140,11875225,11765015);贵州省教育厅青年科技人才成长项目(黔教合KY字[2016]312);国家级大学生创新创业训练计划(201810635045)~~

摘　　要：本文采用超越平均场模型研究了缺中子Ba同位素链114-124Ba的八极形变及其演化规律。计算了Ba链的位能曲面、低能激发谱、电四极跃迁几率、电八极跃迁几率及集体波函数的几率密度分布,并与实验相比较。理论计算较好地再现了Ba核的低能激发结构。位能曲面、低能的负宇称带、较大的B(E3;31^-→01^+)和展宽的几率密度分布表明,114Ba中存在较强的八极关联。116,118Ba具有过渡核特征,而120-124Ba则为典型的四极形变原子核。The beyond-mean-field model is applied to study the octupole deformation and shape transition in 114-124Ba. Potential energy surfaces(PES), low-energy excitation spectra, electric transition rates, and probability density distributions in Ba isotopes are systematically analyzed using a quadrupole-octupole collective Hamiltonian(QOCH) model based on covariant density functional theory. The microscopic QOCH model is shown to accurately describe the empirical trend of low-energy positive-and negative-parity states. The theoretical results of PES,low-lying negative-parity bands, rather large B(E3;31^-→ 01^+), and extended probability density distributions show evidence of strong octupole correlations in 114Ba.116,118Ba present as transitional nuclei, while 120-124Ba are well quadrupole deformed nuclei.

关 键 词：超越平均场模型 八极形变 低能负宇称带 协变密度泛函理论 

分 类 号：O571.53[理学—粒子物理与原子核物理]