Microscopic analysis of octupole shape transitions in neutron-rich actinides with relativistic energy density functional  

作　　者：许众 李志攀 

机构地区：[1]School of Physical Science and Technology, Southwest University, Chongqing 400715, China

出　　处：《Chinese Physics C》2017年第12期76-87,共12页中国物理C（英文版）

基　　金：Supported by National Natural Science Foundation of China(11475140,11575148)

摘　　要：Quadrupole and octupole deformation energy surfaces, low-energy excitation spectra, and electric transition rates in eight neutron-rich isotopic chains – Ra, Th, U, Pu, Cm, Cf, Fm, and No – are systematically analyzed using a quadrupole-octupole collective Hamiltonian model, with parameters determined by constrained reflectionasymmetric and axially-symmetric relativistic mean-field calculations based on the PC-PK1 energy density functional.The theoretical results of low-lying negative-parity bands, odd-even staggering, average octupole deformations β3,and B（E3;31- →01＋） show evidence of a shape transition from nearly spherical to stable octupole-deformed, and finally octupole-soft equilibrium shapes in the neutron-rich actinides. A microscopic mechanism for the onset of stable octupole deformation is also discussed in terms of the evolution of single-nucleon orbitals with deformation.Quadrupole and octupole deformation energy surfaces, low-energy excitation spectra, and electric transition rates in eight neutron-rich isotopic chains – Ra, Th, U, Pu, Cm, Cf, Fm, and No – are systematically analyzed using a quadrupole-octupole collective Hamiltonian model, with parameters determined by constrained reflectionasymmetric and axially-symmetric relativistic mean-field calculations based on the PC-PK1 energy density functional.The theoretical results of low-lying negative-parity bands, odd-even staggering, average octupole deformations β3,and B（E3;31- →01＋） show evidence of a shape transition from nearly spherical to stable octupole-deformed, and finally octupole-soft equilibrium shapes in the neutron-rich actinides. A microscopic mechanism for the onset of stable octupole deformation is also discussed in terms of the evolution of single-nucleon orbitals with deformation.

关 键 词：ocutpole deformation negative-parity band relativistic energy density functional quadrupole-octupolecollective Hamiltonian 

分 类 号：O571[理学—粒子物理与原子核物理]