Theoretical Analysis of Ionic Autoionization Spectra of Lanthanum in the Energy Region of 90650—915—00cm^—1

Eigenquantum defects μα and transformation matrix Uiα of La are calculated from the first principles byrelativistic multichannel theory, and dipole matrix elements Dα are obtained by fitting the experimental spectra.With these parameters, ionic autoionization spectra of lanthanum via an intermediatestate (Xe)5d6d^-1 P1 of La . in the energy region of 90650-91500 cm^-1 are calculated within the framework of multichannel auantum defecttheory. Our calculated spectra are in general agreement with the experimental data.     

延迟和相关效应对Ne原子2p53s1,3P01-2p61S0跃迁的影响

利用多组态Dirac-Fock(MCDF)方法,系统地研究了延迟和相关效应对中性Ne原子2p53s1,3P01-2p61S0电偶极共振和复合跃迁的能量以及跃迁几率(寿命)的影响,给出了相应的跃迁能和辐射寿命,并与最新的实验观测和其他理论计算结果进行了比较.     

Polarization Transfer in the 2pa/2 Photoionization of Magnesium-Like Ions

The inner-shell 2p3/2 ionization of Mg-like Fe^14＋, Cd^36＋, W^62＋ and U^80＋ ions by linear polarized light and the subsequent radiative decay are studied theoretically with the multicon~guration Dirac Fock （MCDF） method and the density matrix theory. Special attention is paid to exploring the influence of the polarization properties of the incident photon and the non-dipole term which arises from the multipole expansion of the electron-photon interaction on the properties of the subsequent x-ray radiation. The results show that there is a linear relationship between the degree of linear polarization of the radiative decay and ones of the incident light, which can be used for diagnosing the polarization of a light source. In addition, with the increasing photon energies, the non- dipole contribution to the alignment of the residual ions, the degree of linear polarization, as well as the angular distribution of the radiative decay following the inner-shell photoionization will also be increased.     

氖原子光电子角分布的理论计算

本文利用密度矩阵理论和Racah代数推导出了光电子角分布的一般计算公式, 并在多组态Dirac-Fock方法基础上发展了计算原子光电离过程中产生的光电子角分布的相对论程序, 利用该程序对氖原子2s和2p光电子角分布的偶极和非偶极参数进行了具体计算, 所得结果与已有文献具有很好的一致性. 在此基础上, 本文讨论了光子与电子相互作用多级展开中的非偶极项以及入射光的极化性质对光电子角分布的影响.     

系统研究氢原子Stark能谱的数值方法Ⅱ—准稳态及其线型

本文通过标度变换，引入ｔ参量，将抛物坐标下分离变量后，稳定外电场下氢原子的Ｓｃｈｒｏｄｉｎｇｅｒ方程消除了耦合，大大地简化了计算。由“有效动能”曲线给出“准稳态”存在的判据。利用波函数渐近表达式的周期性性质，可求出任意ｍ值的氢原子能级随电场变化的解。本文以ｎ＝６时２１条Ｓｔａｒｋ分裂谱的Ｅ－Ｆ曲线为例，说明这种系统计算法的简便。最后通过边接出射波函数与其渐近形式，计算出散射振幅，分析了ＤＣ Ｓｔａ     

Nonradiative charge transfer in collisions of protons with rubidium atoms

The nonradiative charge-transfer cross sections for protons colliding with Rb(5s) atoms are calculated by using the quantum-mechanical molecularorbital close-coupling method in an energy range of 10 3 keV-10 keV.The total and state-selective charge-transfer cross sections are in good agreement with the experimental data in the relatively low energy region.The importance of rotational coupling for chargetransfer process is stressed.Compared with the radiative charge-transfer process,nonradiative charge transfer is a dominant mechanism at energies above 15 eV.The resonance structures of state-selective charge-transfer cross sections arising from the competition among channels are analysed in detail.The radiative and nonradiative charge-transfer rate coefficients from low to high temperature are presented.     

Relativistic RRR-matrix studies of photoionization processes of Ar~(5+)

The 3s–np photoionization processes of the ground state 2P1/2 and the metastable state 2P3/2 of Ar5+ are investigated using our recently developed relativistic R-matrix code, where the interactions between the bound states and the continuum states are included. Both resonance positions and the oscillator strengths are in much better agreement with the absolute experimental measurements by Wang et al. [Wang J C, Lu M, Esteves D, Habibi M, Alna'washi G and Phaneuf R A 2007 Phys. Rev. A 75 062712] with a resolution of 80 meV than their theoretical results. The contributions of the two experimental unresolved transitions are distinguished in our calculations, which show that the transitions from the ground state also make significant contributions to some resonances. Our theoretical results are also in good agreement with the measurements for the first resonance with a higher resolution of 20 meV.     

Debye-screening effect on electron-impact excitation of helium-like Al11+ and Fe24+ ions

Debye-screening effects on the electron-impact excitation (EIE) processes for the dipole-allowed transition 1s$^{2}$ $^{1}{\rm S} \to 1$s2p $^{1}$P in He-like Al$^{11+}$ and Fe$^{24+}$ ions are investigated using the fully relativistic distorted-wave methods with the-Hückel (DH) model potential. Debye-screening effects on the continuum-bound (CB) interaction and target ion are discussed, both of which result in reduction of EIE cross sections. This reduction due to screening on the CB interaction is dominant. The non-spherical and spherical DH potentials are adopted for considering the screening effect on the CB interaction. It is found that the spherical DH potential could significantly overestimate the influence of plasma screening on EIE cross sections for multielectron He-like ions.     

Electron-impact single ionizaiton for W~(4+) and W~(5+)

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.     

Single and double Auger decay of 4f-ionized mercury including cascade and direct processes

Single(SA) and double(DA) Auger decay including cascade and direct processes are investigated for Hg 4 f~(-1) with multiconfiguration Dirac–Fock method and two-step approaches, i.e., knockout and shakeoff mechanisms. Due to the computational effort, only the major transitions are considered to describe the SA and DA decays for the Hg+ions with complex electronic configurations. In order to estimate the Auger transition energies and amplitudes, the reference configuration sets producing the configuration state functions are carefully chosen for balancing electron correlations among the successive singly, doubly and triply ionized mercury. The Auger rates and electron spectra, DA probabilities as well as the populations of the final Hg~(3+)states are obtained. Our results well explain the recent experimental data about the 4 f hole states of Hg[Palaudoux J et al., Phys. Rev. A 91 012513(2015)], and could provide guidance for further studies on complex atoms.Particularly for the DA decay, the contributions of the direct processes, which are neglected in their calculations, are found to be important, accounting for as high as about 38% and 34% of the total DA decays for the 4 f_(7/2)~(-1) and 4 f_(5/2)~(-1), respectively.