基于多组态Dirac-Fock方法和密度矩阵理论,系统地研究了在197 Me V/u的碰撞能量下,Xe^(53+)离子与Xe原子的辐射电子俘获过程(REC)以及电子被俘获到激发态后辐射退激发产生的特征谱线.计算了炮弹Xe^(53+)离子俘获电子到不同壳层np_(1/2,3...基于多组态Dirac-Fock方法和密度矩阵理论,系统地研究了在197 Me V/u的碰撞能量下,Xe^(53+)离子与Xe原子的辐射电子俘获过程(REC)以及电子被俘获到激发态后辐射退激发产生的特征谱线.计算了炮弹Xe^(53+)离子俘获电子到不同壳层np_(1/2,3/2)(n=2—5)的总截面与相应的REC光子能量和角分布,以及由激发组态1snp_(1/2,3/2)(n=2—5)J_f=1向基态1s^2Jd=0辐射退激发的跃迁能量、跃迁概率和特征光子的角分布和线性极化度.计算结果表明,辐射光子具有显著的角各向异性特征.此外,1snp_(3/2)J_f=1→1s^2J_d=0退激发特征光子也显示出很强的线性极化和角各向异性特征,而1snp_(1/2)J_f=1→1s^2J_d=0退激发特征光子的线性极化度趋于零并且角分布也趋于各向同性.展开更多
The angular distribution and polarization of the x-ray photoemission of highly charged helium-like ions is studied following the K-LL dielectronic recombination of initially hydrogen-like ions.Calculation is carried o...The angular distribution and polarization of the x-ray photoemission of highly charged helium-like ions is studied following the K-LL dielectronic recombination of initially hydrogen-like ions.Calculation is carried out within the framework of the density matrix theory combined with the multiconfiguration Dirac-Fock approach.Attention is paid to magnetic sublevel alignment in the resonant intermediate state and to its nonuniform radiative decay processes.It is shown that the Breit interaction between the incident and target electrons plays a significant role for the alignment of the resonant state and thus causes a substantial change in the x-ray emission characteristic,when compared to the incorporation of only the(non-relativistic)Coulomb interaction.The most prominent difference in alignment parameter is found in the 2s2p_(1/2) J=1 resonant state for a wide range of atomic numbers from 9 to 92.For this resonant state of helium-like ions,the Breit interaction becomes significant for ions with nuclear charge Z~30 already.展开更多
Detailed calculations are carried out for the electron-impact excitation cross sections from the ground state to the individual magnetic sublevels of the 1s2s^(2)2p^(3)/2 J=2 excited state of highly-charged beryllium-...Detailed calculations are carried out for the electron-impact excitation cross sections from the ground state to the individual magnetic sublevels of the 1s2s^(2)2p^(3)/2 J=2 excited state of highly-charged beryllium-like ions by using a fully relativistic distorted-wave(RDW)method.The contributions of the Breit interaction to the linear polarization of the 1s2s^(2)2p^(3)/2 J=2→1s22s2 J=0 magnetic quadrupole(M2)line are investigated systematically for the beryllium isoelectronic sequence with 42≤Z≤92.It is found that the Breit interaction depolarizes significantly the linear polarization of the M2 fluorescence radiation and that these depolarization effects increase as the incident electron energy and/or the atomic number is enlarged.展开更多
The dissipation phenomenon in the heavy-ion reaction at incident energy near the Fermi energy is studied by simulating the reaction ^(129)Xe+^(129)Sn with the isospin-dependent quantum molecular dynamics model.The cal...The dissipation phenomenon in the heavy-ion reaction at incident energy near the Fermi energy is studied by simulating the reaction ^(129)Xe+^(129)Sn with the isospin-dependent quantum molecular dynamics model.The calculations involving a proper prescription of implementing the Pauli exclusion principle show that the isotropy ratio measured by free protons emitted in the reaction at energy slightly higher than the Fermi energy is in agreement with the experimental data recently released by the INDRA collaboration.A feasible value of the Pauli-blocking factor is estimated by comparing the theoretical results with the experimental data for the energy range considered here.展开更多
Electron-impact single ionization cross sections for W^(q+)(q = 4–5) were calculated using the flexible atomic code(FAC) in the level-to-level distorted-wave method, considering the explicit branching ratio. The calc...Electron-impact single ionization cross sections for W^(q+)(q = 4–5) were calculated using the flexible atomic code(FAC) in the level-to-level distorted-wave method, considering the explicit branching ratio. The calculated cross sections are compared with the available theoretical and experiment results in detail. In the case of the contribution from the same channles as the available theoretical results, all of the calculated ionization cross sections agree with the experimental measured cross sections. But the present calculated results are larger than the experimental measurement when all channels contributions are included. Some important channels excitation autoionization(EA) contributions, such as the excitation to higher higher nl subshell from 4 f and 5[s,p], were not included into the available theoretical calculation. In general, the distorted-wave(DW) results are overestimated.展开更多
In this work,the KLL dielectronic recombination (DR) processes of highly charged He-like to O-like xenon ions are studied systematically by using a DR program,which is based on the multi-configuration Dirac-Fock (MCDF...In this work,the KLL dielectronic recombination (DR) processes of highly charged He-like to O-like xenon ions are studied systematically by using a DR program,which is based on the multi-configuration Dirac-Fock (MCDF) method.The KLL DR resonant energies and the corresponding resonant strengths are calculated,emphasizing especially the effect of the Breit interaction on the DR strengths.The theoretical KLL DR spectra are obtained and compared with the latest experimental results obtained in the Shanghai Electron Beam Ion Trap.展开更多
基金The National Natural Science Foundation of China(Nos.11264033,11464040,11265013,11504421)the Natural Science Foundation of Gansu Province(No.1506RJZE112)+1 种基金the Scientific Research Foundation of Higher Education of Gansu Province(No.2014A-104)the Higher School in Gansu Province Basic Scientific Research Expenses(No.2050205)
基金National Natural Science Foundation of China(Nos.11764035,11964031,12064037)Natural Science Foundation of Gansu Province(Nos.18JR3RE246,20JR10RA793)Tianshui Normal University“QinglanTalents”Project。
文摘基于多组态Dirac-Fock方法和密度矩阵理论,系统地研究了在197 Me V/u的碰撞能量下,Xe^(53+)离子与Xe原子的辐射电子俘获过程(REC)以及电子被俘获到激发态后辐射退激发产生的特征谱线.计算了炮弹Xe^(53+)离子俘获电子到不同壳层np_(1/2,3/2)(n=2—5)的总截面与相应的REC光子能量和角分布,以及由激发组态1snp_(1/2,3/2)(n=2—5)J_f=1向基态1s^2Jd=0辐射退激发的跃迁能量、跃迁概率和特征光子的角分布和线性极化度.计算结果表明,辐射光子具有显著的角各向异性特征.此外,1snp_(3/2)J_f=1→1s^2J_d=0退激发特征光子也显示出很强的线性极化和角各向异性特征,而1snp_(1/2)J_f=1→1s^2J_d=0退激发特征光子的线性极化度趋于零并且角分布也趋于各向同性.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274254,91126007,10964010,11264033,and 11147018.
文摘The angular distribution and polarization of the x-ray photoemission of highly charged helium-like ions is studied following the K-LL dielectronic recombination of initially hydrogen-like ions.Calculation is carried out within the framework of the density matrix theory combined with the multiconfiguration Dirac-Fock approach.Attention is paid to magnetic sublevel alignment in the resonant intermediate state and to its nonuniform radiative decay processes.It is shown that the Breit interaction between the incident and target electrons plays a significant role for the alignment of the resonant state and thus causes a substantial change in the x-ray emission characteristic,when compared to the incorporation of only the(non-relativistic)Coulomb interaction.The most prominent difference in alignment parameter is found in the 2s2p_(1/2) J=1 resonant state for a wide range of atomic numbers from 9 to 92.For this resonant state of helium-like ions,the Breit interaction becomes significant for ions with nuclear charge Z~30 already.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274254,91126007 and 11264033.
文摘Detailed calculations are carried out for the electron-impact excitation cross sections from the ground state to the individual magnetic sublevels of the 1s2s^(2)2p^(3)/2 J=2 excited state of highly-charged beryllium-like ions by using a fully relativistic distorted-wave(RDW)method.The contributions of the Breit interaction to the linear polarization of the 1s2s^(2)2p^(3)/2 J=2→1s22s2 J=0 magnetic quadrupole(M2)line are investigated systematically for the beryllium isoelectronic sequence with 42≤Z≤92.It is found that the Breit interaction depolarizes significantly the linear polarization of the M2 fluorescence radiation and that these depolarization effects increase as the incident electron energy and/or the atomic number is enlarged.
基金Supported by the National Natural Science Foundation Of China under Grant Nos 11265013,11175074,11264033 and 11464040
文摘The dissipation phenomenon in the heavy-ion reaction at incident energy near the Fermi energy is studied by simulating the reaction ^(129)Xe+^(129)Sn with the isospin-dependent quantum molecular dynamics model.The calculations involving a proper prescription of implementing the Pauli exclusion principle show that the isotropy ratio measured by free protons emitted in the reaction at energy slightly higher than the Fermi energy is in agreement with the experimental data recently released by the INDRA collaboration.A feasible value of the Pauli-blocking factor is estimated by comparing the theoretical results with the experimental data for the energy range considered here.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.2017YFA0402300,11464042,11564036,11774292,and 11464040)the Basic Scientific Research Foundation for Institution of Higher Learning of Gansu Province,China
文摘Electron-impact single ionization cross sections for W^(q+)(q = 4–5) were calculated using the flexible atomic code(FAC) in the level-to-level distorted-wave method, considering the explicit branching ratio. The calculated cross sections are compared with the available theoretical and experiment results in detail. In the case of the contribution from the same channles as the available theoretical results, all of the calculated ionization cross sections agree with the experimental measured cross sections. But the present calculated results are larger than the experimental measurement when all channels contributions are included. Some important channels excitation autoionization(EA) contributions, such as the excitation to higher higher nl subshell from 4 f and 5[s,p], were not included into the available theoretical calculation. In general, the distorted-wave(DW) results are overestimated.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10774122 and 10876028)the Natural ScienceFoundation of Gansu Province,China(Grant No.1010RJZA014)the Foundation of Northwest Normal University,China(Grant No.NWNU-KJCXGC-03-72)
文摘In this work,the KLL dielectronic recombination (DR) processes of highly charged He-like to O-like xenon ions are studied systematically by using a DR program,which is based on the multi-configuration Dirac-Fock (MCDF) method.The KLL DR resonant energies and the corresponding resonant strengths are calculated,emphasizing especially the effect of the Breit interaction on the DR strengths.The theoretical KLL DR spectra are obtained and compared with the latest experimental results obtained in the Shanghai Electron Beam Ion Trap.
