N=Z原子核^(64)Ge可能存在的三轴形变  

Possible triaxial deformation in N=Z nucleus germanium-64

作　　者：沈水法 王华磊[5] 孟海燕[5] 阎玉鹏 沈洁洁 王飞鹏 蒋海滨[3] 包莉娜 Shen Shui-Fa;Wang Hua-Lei;Meng Hai-Yan;Yan Yu-Peng;Shen Jie-Jie;Wang Fei-Peng;Jiang Hai-Bin;Bao Li-Na(School of Intelligent Manufacturing,Zhejiang Guangsha Vocational and Technical University of Construction,Zhejiang,Jinhua 322100,China;Institute of Nuclear Energy Safety Technology,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Anhui,Hefei 230031,China;School of Electronic,Electrical Engineering and Physics,Fujian University of Technology,Fujian,Fuzhou 350118,China;Key Laboratory of High Precision Nuclear Spectroscopy,Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China;School of Physics,Zhengzhou University,Zhengzhou 450001,China;School of Physics,Suranaree University of Technology,Nakhon Ratchasima 30000,Thailand;Thailand Center of Excellence in Physics ThEP,Commission on Higher Education,Bangkok 10400,Thailand;Division of Health Sciences,Hangzhou Normal University,Zhejiang,Hangzhou 310012,China;Department of Basic Sciences,Army Academy of Artillery and Air Defense,Anhui,Hefei 230031,China)

机构地区：[1]浙江广厦建设职业技术大学智能制造学院,金华322100 [2]中国科学院合肥物质科学研究院核能安全技术研究所,合肥230031 [3]福建工程学院电子电气与物理学院,福州350118 [4]中国科学院近代物理研究所高精度核谱学重点实验室,兰州730000 [5]郑州大学物理学院,郑州450001 [6]苏拉娜里理工大学物理学院,那空叻差是玛300007 [7]泰国高等教育委员会物理卓越中心ThEP,曼谷104008 [8]杭州师范大学医学部,杭州310012 [9]陆军炮兵防空兵学院,合肥230031

出　　处：《物理学报》2021年第19期46-51,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11065001);中国科学院高精度核谱学重点实验室开放课题资助的课题。

摘　　要：为寻找核态可能存在的三轴形变,用对力-形变-转动频率自洽推转壳模型对锗和硒同位素进行了总转动能面计算.计算是在四极形变(β_2,γ)网格中进行的,且十六极形变β_4可变.在锗同位素中发现了由64Ge的三轴、^(66)Ge的扁椭、再经三轴、向长椭形变的形状相变.一般来说Ge和Se同位素具有γ软性形状,导致了显著的动力学三轴效应,计算中没有证据表明存在基态下的刚性三轴性.在^(64,74)Ge中发现基态和集体转动态下γ=-30°的三轴形变,这是三轴形变的极限.本文重点讨论N=Z核^(64)Ge可能存在的三轴形变,给出了基于唯象Woods-Saxon势下的单粒子能级信息,并对N=Z核^(64)Ge三轴形变的产生机理进行了讨论.Evidence for nonaxialγdeformations has been widely found in collective rotational states.Theγdeformation has led to very interesting characteristics of nuclear motions,such as wobbling,chiral band,and signature inversion in rotational states.There is an interesting question;why the nonaxialγdeformation is not favored in the ground states of even-even(e-e)nuclei.The quest for stable triaxial shapes in the ground states of e-e nuclei,with a maximum triaxial deformation of|γ|≈30°,is still a major theme in nuclear structure.In the present work,we use the cranked Woods-Saxon(WS)shell model to investigate possible triaxial shapes in ground and collective rotational states.Total-Routhian-surface calculations by means of the pairingdeformation-frequency self-consistent cranked shell model are carried out for even-even germanium and selenium isotopes,in order to search for possible triaxial deformations of nuclear states.Calculations are performed in the lattice of quadrupole(β_(2),γ)deformations with the hexadecapoleβ_(4) variation.In fact,at each grid point of the quadrupole deformation(β_(2),γ)lattice,the calculated energy is minimized with respect to the hexadecapole deformationβ_(4).The shape phase transition from triaxial shape in 64Ge,oblate shape in ^(66)Ge,again through triaxiality,to prolate deformations is found in germanium isotopes.In general,the Ge and Se isotopes haveγ-soft shapes,resulting in significant dynamical triaxial effect.There is no evidence in the calculations pointing toward rigid triaxiality in ground states.The triaxiality ofγ=-30°for the ground and collective rotational states,that is the limit of triaxial shape,is found in 64,74 Ge.One should also note that the depth of the triaxial minimum increases with rotational frequency increasing in these two nuclei.The present work focuses on the possible triaxial deformation of N=Z nucleus 64 Ge.Single-particle level diagrams can give a further understanding of the origin of the triaxiality.Based on the information about single-parti

关 键 词：三轴形变 总转动能面 形状演化 

分 类 号：O571[理学—粒子物理与原子核物理]