The observed low-lying K=5/2^(±) positive-and negative-parity bands in the stable nucleus ^(153)Eu are investigated using the reflection-asymmetric triaxial particle rotor model.The experimental energy spectra,en...The observed low-lying K=5/2^(±) positive-and negative-parity bands in the stable nucleus ^(153)Eu are investigated using the reflection-asymmetric triaxial particle rotor model.The experimental energy spectra,energy staggering parameters,and intraband E2 and M1 transition probabilities are well reproduced.The calculated interband B(E1)values are found to depend sensitively on the octupole deformation parameter β_(30),although the energy spectra and intraband E2 and M1 transitions can be reproduced without the octupole degree of freedom.The observed enhanced E1 transition probabilities can be reproduced with β_(30)=0.05.The detailed analysis of the intrinsic wave functions shows these nearly degenerate positive-and negative-parity bands are built on two individual proton configurations,i.e.,dominated by πg_(7/2)[Ω=5/2]and πh_(11/2)[Ω=5/2],respectively,which differs from the parity doublet bands built on a single parity-mixed configuration.展开更多
The potential energy surfaces of even-even 142-156Ba are investigated in the constrained reflectionasymmetric relativistic mean-field approach with parameter set PK1. It is shown that for the ground states, 142Ba is n...The potential energy surfaces of even-even 142-156Ba are investigated in the constrained reflectionasymmetric relativistic mean-field approach with parameter set PK1. It is shown that for the ground states, 142Ba is near spherical,156Ba well quadrupole-deformed, and in between 144-154Ba octupole deformed. In particular, the nuclei 148,150Ba with N=92, 94 have the largest octupole deformations. By including the octupole degree of freedom, energy gaps N = 88, N = 94 and Z = 56 near Fermi surfaces for the singleparticle levels in 148Ba with β2 ～ 0.26 and β3 ～ 0.17 are found. Furthermore, the performance of the octupole deformation driving pairs （ν2f7/2, ν1i13/2） and （π2d5/2, π1h11/2） is demonstrated by analyzing the singleparticle levels near Fermi surfaces in 148Ba.展开更多
Single particles moving in a reflection-asymmetric potential are investigated by solving the Schr6dinger equation of the reflectionasymmetric Nilsson Hamiltonian with the imaginary time method in 3D lattice space and ...Single particles moving in a reflection-asymmetric potential are investigated by solving the Schr6dinger equation of the reflectionasymmetric Nilsson Hamiltonian with the imaginary time method in 3D lattice space and the harmonic oscillator basis expansion method. In the 3D lattice calculation, the l2 divergence problem is avoided by introducing a damping function, and the（l2）N term in the non-spherical case is calculated by introducing an equivalent N-independent operator. The efficiency of these numerical techniques is demonstrated by solving the spherical Nilsson Hamiltonian in 3D lattice space. The evolution of the single-particle levels in a reflection-asvmmetric ootential is obtained and discussed bv the above two numerical methods, and their consistencv is shown in the obtained single-particle energies with the differences smaller than 10-4[hω0]展开更多
The octupole correlations of the K^(π)=5/2^(+)ground state and the rotational spectrum built on it in^(229)Th are studied using the microscopic relativistic density functional theory on a three-dimensional lattice sp...The octupole correlations of the K^(π)=5/2^(+)ground state and the rotational spectrum built on it in^(229)Th are studied using the microscopic relativistic density functional theory on a three-dimensional lattice space and the reflection-asymmetric triaxial particle rotor model.It is found that^(229)Th has a ground state with static axial octupole and quadrupole deformations.The occurrence of octupole correlations,driven by the octupole deformation,is analyzed through the evolution of single-particle levels around the Fermi surface.The experimental energy spectrum and the electromagnetic transition probabilities,including B(E2)and B(M1),are reasonably well reproduced.展开更多
基金Supported partly by the National Key R&D Program of China(2024YFE0109803)the National Natural Science Foundation of China(12205097,11935003,12141501)+2 种基金the Fundamental Research Funds for the Central Universities(2024MS071)the State Key Laboratory of Nuclear Physics and Technology,Peking University(NPT2023ZX03)the High Performance Computing Platform of Peking University。
文摘The observed low-lying K=5/2^(±) positive-and negative-parity bands in the stable nucleus ^(153)Eu are investigated using the reflection-asymmetric triaxial particle rotor model.The experimental energy spectra,energy staggering parameters,and intraband E2 and M1 transition probabilities are well reproduced.The calculated interband B(E1)values are found to depend sensitively on the octupole deformation parameter β_(30),although the energy spectra and intraband E2 and M1 transitions can be reproduced without the octupole degree of freedom.The observed enhanced E1 transition probabilities can be reproduced with β_(30)=0.05.The detailed analysis of the intrinsic wave functions shows these nearly degenerate positive-and negative-parity bands are built on two individual proton configurations,i.e.,dominated by πg_(7/2)[Ω=5/2]and πh_(11/2)[Ω=5/2],respectively,which differs from the parity doublet bands built on a single parity-mixed configuration.
基金Supported by Foundation of He’nan Educational Committee (200614003)Young Backbone Teacher Support Program of He’nan Polytechnic University,China Postdoctoral Science Foundation,Major State Basic Research Developing Program(2007CB815000)National Natural Science Foundation of China (10775004,10975007,10975008)
文摘The potential energy surfaces of even-even 142-156Ba are investigated in the constrained reflectionasymmetric relativistic mean-field approach with parameter set PK1. It is shown that for the ground states, 142Ba is near spherical,156Ba well quadrupole-deformed, and in between 144-154Ba octupole deformed. In particular, the nuclei 148,150Ba with N=92, 94 have the largest octupole deformations. By including the octupole degree of freedom, energy gaps N = 88, N = 94 and Z = 56 near Fermi surfaces for the singleparticle levels in 148Ba with β2 ～ 0.26 and β3 ～ 0.17 are found. Furthermore, the performance of the octupole deformation driving pairs （ν2f7/2, ν1i13/2） and （π2d5/2, π1h11/2） is demonstrated by analyzing the singleparticle levels near Fermi surfaces in 148Ba.
基金supported by the National Basic Research Program of China (Grant No. 2013CB834400)the National Natural Science Foundation of China (Grants Nos. 11335002, 11375015, 11461141002, and 11621131001)
文摘Single particles moving in a reflection-asymmetric potential are investigated by solving the Schr6dinger equation of the reflectionasymmetric Nilsson Hamiltonian with the imaginary time method in 3D lattice space and the harmonic oscillator basis expansion method. In the 3D lattice calculation, the l2 divergence problem is avoided by introducing a damping function, and the（l2）N term in the non-spherical case is calculated by introducing an equivalent N-independent operator. The efficiency of these numerical techniques is demonstrated by solving the spherical Nilsson Hamiltonian in 3D lattice space. The evolution of the single-particle levels in a reflection-asvmmetric ootential is obtained and discussed bv the above two numerical methods, and their consistencv is shown in the obtained single-particle energies with the differences smaller than 10-4[hω0]
基金supported by the National Natural Science Foundation of China(Grant Nos.12205097,12141501,12475117,and 12435006)the National Key Laboratory of Neutron Science and Technology(Grant No.NST202401016)+1 种基金the National Key R&D Program of China(Grant Nos.2024YFA1612600 and 2024YFE0109803)the High-performance Computing Platform of Peking University。
文摘The octupole correlations of the K^(π)=5/2^(+)ground state and the rotational spectrum built on it in^(229)Th are studied using the microscopic relativistic density functional theory on a three-dimensional lattice space and the reflection-asymmetric triaxial particle rotor model.It is found that^(229)Th has a ground state with static axial octupole and quadrupole deformations.The occurrence of octupole correlations,driven by the octupole deformation,is analyzed through the evolution of single-particle levels around the Fermi surface.The experimental energy spectrum and the electromagnetic transition probabilities,including B(E2)and B(M1),are reasonably well reproduced.
