Dielectronic recombination of Co-like tantalum

Ab initio calculation of the total dielectronic recombination (DR) rate coefficient from the ground state of Co-like tantalum is performed using the relativistic distorted-wave approximation with configuration interaction. The contributions to the total DR rate coefficients are explicitly calculated from the complexes of Ni-like tantalum: 3s²3p⁶3d_3/2³ 3d_5/2⁶ n'l', 3s²3p⁵3d¹⁰n'l', 3s3p⁶3d¹⁰n'l', 3s²3p⁶3d⁸4ln'l', 3s²3p⁵3d⁹4ln'l' and 3s3p⁶3d⁹4ln'l' with n' ≤ 25, and 3s²3p⁶3d⁸5ln'l' with n' ≤ 9. The l' and n' dependences of partial DR rate coefficients are investigated. The contributions from higher n'complexes are evaluated by a level-by-level extrapolation method. The total DR rate coefficients mainly come from the complex series 3s²3p⁶3d⁸4ln'l', 3s²3p⁵3d⁹4ln'l' and are fitted to an empirical formula with high accuracy. Comparison of the present results with those of other works shows that the previously published data underestimate significantly the DR rates of Co-like tantalum.     

Systematic theoretical study of dielectronic recombination for helium-like isoelectronic sequence

Dielectronic recombination cross sections and rate coefficients of He-like isoelectronic sequence are systematically calculated employing the relativistic Flexible Atomic Code (FAC). The calculated DR resonance strengths, cross sections and rate coefficients are in good agreement with other experimental and theoretical results. The effects of radiative cascades on DR cross sections and the variation of DR branching ratio with different DR resonance and atomic numbers Z are studied. The n⁻³ scaling law is also checked and used to extrapolate rate coefficients. And analytic formulas are used to fit the total rate coefficients with respect to both T and Z for helium-like isoelectronic sequence.     

Resonance excitation process for Ni-like gold

A detailed and large-scale calculation on the resonant excitation rate coefficients from the ground state to the 106 fine-structure levels belonging to 3l¹⁷4l^′(l=0,1,2;l^′=0,1,2,3) configurations of Ni-like gold have been performed using the relativistic distorted-wave approximation. The contributions through all possible Cu-like doubly excited states 3l¹⁷4l^′n^″l^″and 3l¹⁷5l^′n^″l^″(n^″≤15,l^″≤8) are calculated explicitly. The radiative damping effects on resonant excitation rates are studied. Significant effects arising from decays to autoionizing levels are also investigated. The n⁻³scaling law is investigated and is used to obtain the contributions from high-n configurations. Contributions from resonant excitation are found to be as important as direct excitation processes for most transitions. In some cases, resonant excitation can enhance the excitation rate coefficients by an order of magnitude. In addition, the total dielectronic recombination rate coefficients of Ni-like gold are also presented and compared with other works.     

Radiative rates and electron impact excitation rate coefficients for H-like Fe XXVI

In this paper we report on calculations on energy levels, radiative rates, collision strengths, and effective collision strengths for transitions among the lowest 36 levels of the n≤6 configurations of H-like Fe XXVI. Flexible atomic code (FAC) is adopted for the calculation. Energy levels and radiative rates are calculated within relativistic configuration-interaction method. Direct excitation collision strength is calculated using relativistic distorted-wave approximation. Resonance contributions through the relevant He-like doubly excited n^′l^′n^″l^″ configurations with n^′≤7 and n^″≤75 are explicitly taken into account using the isolated process and isolated resonances approximation. We present the radiative rates, oscillator strengths, and line strengths for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions among the 36 levels. Furthermore, collision strengths and effective collision strengths are reported for all the 630 transitions among the above 36 levels over a wide energy (temperature) range up to 25 keV . Extensive comparisons are made with earlier available results and the accuracy of the data is assessed.     

钨离子双电子复合过程的理论研究

摘要: 利用全相对论组态相互作用理论方法, 研究了W28+离子由基态俘获一个电子形成双激发态(3d104s24p64d10 )-1 nln''l''(n = 4~6, n'' = 4~15)的双电子复合(DR)过程. 比较分析了3s、3p、3d、4s、4p和4d电子激发对DR速率系数的贡献, 分析了3d、4s、4p和4d电子激发的DR速率系数随轨道量子数l'' 的变化. 考虑和已有的计算完全相同的初态, 中间双激发态以及辐射和俄歇末态的情况下, 得到了和已有的计算符合很好的结果. 在综合了分析得到的对W28+离子DR过程有明显贡献的各种因素后,进一步得到了总DR速率系数. 其中, 考虑DAC效应对总DR速率系数有不可忽略的影响. 对DR速率系数进行了参数拟合, 拟合值与计算值的偏差小于1％.     

钨离子双电子复合过程的理论研究

利用全相对论组态相互作用理论方法, 研究了W28+离子由基态俘获一个电子形成双激发态(3d104s24p64d10 )-1 nln'l'(n = 4~6, n' = 4~15)的双电子复合(DR)过程. 比较分析了3s、3p、3d、4s、4p和4d电子激发对DR速率系数的贡献, 分析了3d、4s、4p和4d电子激发的DR速率系数随轨道量子数l' 的变化. 考虑和已有的计算完全相同的初态, 中间双激发态以及辐射和俄歇末态的情况下, 得到了和已有的计算符合很好的结果. 在综合了分析得到的对W28+离子DR过程有明显贡献的各种因素后,进一步得到了总DR速率系数. 其中, 考虑DAC效应对总DR速率系数有不可忽略的影响. 对DR速率系数进行了参数拟合, 拟合值与计算值的偏差小于1％.     

类铷W37+离子双电子复合速率系数的理论研究

 利用全相对论组态相互作用理论方法,研究了类铷W³⁷⁺离子从基组态3s²3p⁶3d¹⁰4s²4p⁶4d经过双激发态(3s²3p⁶3d¹⁰4s²4p⁶4d)^-1nln′l′(n,n′=4,5)的双电子复合过程,得到了该离子在温度为1~5×10⁴ eV范围内的总双电子复合速率系数。分析比较了不同电子激发的双电子复合速率系数,结果表明:4p电子激发的双电子复合速率系数在低温时给出了主要贡献,而3d的贡献在高温时突出。由于强组态相互作用,两电子一光子跃迁对双电子复合速率系数的贡献不可忽略,其中辐射跃迁4p⁵4d5d5f-4p⁶4f5d的贡献是双激发态4p⁵4d5d5f总的双电子复合速率系数的5%。对双电子复合、辐射复合以及三体复合速率系数的比较表明,在所研究的温度范围内双电子复合速率系数最大。     

Rapid evaluation for dielectronic recombination rate coefficients of Ni－like ions Gd and Ta

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类氦氪离子双电子复合的相对论计算

本文采用相对论性的Flexible Atomic Code (FAC)程序计算类氦氪离子的双电子复合截面及速率系数。其中自电离速率的计算采用相对论扭曲波近似，并考虑了组态相互作用的影响。文中还将所得的自电离和总辐射速率与采用MCDF和HULLAC计算得到的结果作了比较。我们检验了n-3标度律的有效性并用它对速率系数做了外推。文中还讨论了辐射分支比随不同共振峰和原子序数的变化以及级联辐射的影响。     

Variation of dielectronic satellite intensity factors with n for dielectronic recombination processes in selected lithium—like ions

Satellite intensity factors F^*₂(s→f) have been calculated for the 1s²2s+εl→(1s²3l′nl″)^*→1s²2sml''+hν dielectronic recombination processes of lithium-like V, Cu, Se, Ag and Ba ions. The relevant atomic parameters have been calculated explicitly for all intermediate resonance states |s〉≡|1s²3l′nl″SLJ〉 with n=3－9 in the intermediate coupling scheme. The 1/n³ scaling, which has often been used in extrapolating F^*(s→f) for n≥4, is tested against these values of F^*₂(s→f).     

The KLL dielectronic recombination processes for highly charged krypton, iodine and barium ions

The KLL dielectronic recombination (DR) processes of ions from highly charged helium-like to oxygen-like krypton, iodine and barium ions are studied systematically in the relativistic distorted-wave approximation with configuration interaction. The KLL DR resonant energies, the corresponding resonant strengths and the theoretical spectra for each highly charged ion species are obtained. The results accord well with other available values. The behaviour of KLL resonant strengths for He-like ions with atomic number Z is analysed.     

Calculation of dielectronic recombination cross sections and rate coefficients for heliumlike carbon

A simplified relativistic configuration interaction method is used to calculate the dielectronic recombination cross sections and rate coefficients for heliumlike carbon. In this method, the infinite resonant doubly excited states can be treated conveniently in the frame of Quantum Defect Theory. Our calculated cross sections are in agreements with the experimental measurements except for the 1s2lnl'(n=6,7) resonances. The total energy-integrated cross sections and rate coefficients over all dielectronic resonances are in agreements with the experimental measurements within percent. Received: 7 July 1997 / Revised: 7 October 1997 / Accepted: 8 December 1997     

Relativistic calculations of electron-impact ionization for highly charged hydrogen-like ions

Electron-impact ionization cross-sections and rate coefficients of the 1s ground state for H-like C, O, Mg, Ar, Fe, Cu, As, Kr, Y, Mo ions with incident electron energies up to 15 times the ionization threshold energy have been systematically calculated by the relativistic distorted-wave Born exchange (DWBE) approximation. The comparison of the result with the experimental data, other theoretical calculations and recommended values shows the very good agreement. The influence from relativistic and the lowest order QED effect in the calculation is discussed. The calculated ionization cross-sections are fitted by empirical formulas. These fits can be readily integrated over a relativistic Maxwellian electron distribution function to obtain rate coefficient for plasma modeling.     

脉冲变压器锥形绕组感应系数矩阵简化计算方法

 在进行脉冲变压器多匝数（实际变压器绕组匝数多达4000以上）锥形绕组电压分布仿真时,绕组感应系数矩阵巨大的计算量是制约其实现的瓶颈之一。为了克服此瓶颈,研究了绕组感应系数矩阵的规律性,指出感应系数存在端部效应,且线圈间的互有感应系数随间距衰减很快。在此基础上提出了脉冲变压器锥形绕组感应系数矩阵的简化计算方法,对多匝数绕组,该方法能传统方法所需的n(n+1)/2步减少至2n+25（n为绕组匝数）,大大减少了计算量,使多匝数绕组的仿真计算成为可能。     

相对论速调管振荡器中两个调制腔耦合系数的计算

 用场方法研究了相对论速调管振荡器中两个调制腔的耦合,解析地得到了两腔耦合系数与腔和波导的尺寸、间隙及两腔之间的距离等参数之间的关系。耦合系数的数值与由耦合与否腔的频率测量确定的实验结果在数量级上符合得较好。     

Static dissolution rate of tungsten film versus chemical adjustments of a reused slurry for chemical mechanical polishing

Tungsten is widely used as deposited layer for the multi-level interconnection structures of wafers. The chemical composition of abrasive slurry plays an important role in chemical mechanical polishing (CMP) process. Removal of tungsten is driven by complex oxidation mechanisms between slurry components. The slurry for tungsten CMP generally contains oxidizer, iron catalyst, complexing agents and stabilizers in a pH adjusted solution of abrasive particles. Interaction between iron complex and H₂O₂ in the slurry is the main factor governing the chemical mode of material removal, oxidation potencies and kinetics.In this study, we investigate the effects of chemical additives in silica (SiO₂)-based slurry on the removal rate of the tungsten film. Experiments were carried out in static batch as a preliminary study to understand and optimize chemical mechanisms in CMP-Tungsten process. Experiment designs were conducted to understand the influence of the chemical additives on the main performances of W-CMP. Used slurry, concentrated and retreated with chemical adjustments, is compared to the original slurry as a reference.