Extreme ultraviolet and x-ray transition wavelengths in Rb XXIV

Energy levels, radiative rates, oscillator strengths and line strengths are reported for transitions among the lowest 97 levels of the(1s22s22p6) 3s23p2, 3s23p3 d, 3s3p3, 3p4, 3s3p23 d, and 3s23d2 configurations of Rb XXIV. A multiconfiguration Dirac–Fock(MCDF) method is adopted for the calculations. Radiative rates, oscillator strengths, and line strengths are provided for all electric dipole(E1), magnetic dipole(M1), electric quadrupole(E2), and magnetic quadrupole(M2)transitions from the ground level to all 97 levels, although calculations are performed for a much larger number of levels.To achieve the accuracy of the data, comparisons are provided with similar data obtained from the Flexible Atomic Code(FAC) and also with the available theoretical and experimental results. Our energy levels are found to be accurate to better than 1.2%. Wavelengths calculated are found to lie in EUV(extreme ultraviolet) and x-ray regions. Additionally, lifetimes for all 97 levels are obtained for the first time.     

Energy levels and transition data of 3p63d8 and 3p53d9 configurations in Fe-like ions (Z = 57, 60, 62, 64, 65)

Atomic data of highly charged ions (HCIs) offer an attractive means for plasma diagnostic and stars identification, and the investigations on atomic data are highly desirable. Herein, based on the fully relativistic multi-configuration Dirac-Hartree-Fock (MCDHF) method, we have performed calculations of the fine-structure energy levels, wavelengths, transition rates, oscillator strengths, and line strengths for the lowest 21 states of 3p⁶3d⁸-3p⁵3d⁹ electric dipole (E1) transitions configurations in Fe-like ions (Z = 57, 60, 62, 64, 65). The correlation effects of valence-valence (VV) and core-valence (CV) electrons were systematically considered. In addition, we have taken into account transverse-photon (Breit) interaction and quantum electrodynamics (QED) corrections to treat accurately the atomic state wave functions in the final relativistic configuration interaction (RCI) calculations. Our calculated energy levels and transition wavelengths are in excellent agreement with the available experimental and theoretical results. Most importantly, we predicted some new transition parameters that have not yet been reported. These data would further provide critical insights into better analyzing the physical processes of various astrophysical plasmas.     

Extreme ultraviolet and soft x-ray laser emission from Ni-like Nd ions

We use the energy levels, transition probabilities, and effective collision strengths for the states 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ and 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁹ 4 l (l = s, p, d, and f) of a nickel-like Nd ion to determine reduced population for 55 fine-structure levels over a wide range of electron density values (from 10²⁰ to 4 · 10²² cm ⁻³) at various electron plasma temperatures in the range of 1–2 keV. We find the gain coefficients for those transitions with the positive population inversion factor and show their dependences on the electron density.     

Stark broadening of ar VIII spectral lines

Using the semiclassical perturbation method, we consider, for nine Ar VIII transitions, widths and shifts of spectral lines that are due to collisions with electrons, protons, and ions of He III ut a perturbing particle density of 10¹⁸ cm⁻³ and temperatures between 200,000 and 3,000,000 K. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 286–288, May–June, 2000.     

Stark broadening of Y III spectral lines

Using a semiclassical approach, we have considered electron-, proton-, and ionized helium-impact line width and shifts for 32 Y III multiplets. Published in Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 4, pp. 476–481, July–August, 1998.     

The spectral lines of highly charged gold ions

Extreme ultraviolet spectra of highly charged gold were produced with an electron beam ion trap at the University of Electro-Communications, Tokyo. The X-ray spectra (3240–3360?eV) of Au with well-defined maximum charge states ranging from Cu- to Se-like ions were recorded. Guided by configuration interaction calculations, the strongest 3d–5f transitions have been well defined.     

高度电离的锗激光等离子体X射线谱的辨认

本文结合理论计算得到的锗类钠、类氖、类氟、类氧离子的振子强度,对平面晶体谱仪拍摄的锗激光等离子体X射线谱,波长在6～10(?)范围内的40多条谱线进行了分类辨认.     

平面晶体谱仪弯曲谱线波长定标方法

为了满足激光等离子体X射线光谱测量的需要,提出了一种利用平面晶体谱仪记录得到的弯曲谱线来进行波长标定的新方法。传统的参考谱线法需要已知两条以上谱线的确切波长才能进行波长标定,而利用弯曲谱线可以在不知道任何谱线信息的情况下进行波长标定。通过对实验中所获得的铝等离子体Heα自发射谱线弯曲图像的分析,得到在目前所使用的谱仪条件下,该方法的波长定标精度可以达到2×10-4 nm。     

Comment on “Atomic structure calculations for F-like tungsten” by S. Aggarwal [Chin. Phys B 23(2014) 093203]

Recently, S. Aggarwal [Chin. Phys. B 23 (2014) 093203] reported energy levels, radiative rates, and the lifetimes for the lowest 60 levels belonging to the 2s²2p⁵, 2s2p⁶, and 2s²2p⁴3l configurations of F-like tungsten. There is no discrepancy for his calculated energies for the levels and the radiative rates for the limited number of E1 transitions, but the reported results for the lifetimes are highly inaccurate. According to our calculations, errors in his reported lifetimes are up to 6 orders of magnitude for several levels. Here we report the correct lifetimes for future comparisons and applications, and also explain the reason for the discrepancies.     

VN分子R线系跃迁结构的研究与分析

本文借助孙卫国课题组建立的能精确计算双原子分子R线系发射谱线的物理公式,利用实验上获得的低振动态跃迁谱线数据研究了电极材料VN分子电子态f¹Φ–a¹Δ以及电子态d¹∑⁺–X³Δ₁等跃迁体系的（0,0）跃迁带的R线系发射谱线. 从理论上预言了实验上难以获得的该跃迁带R线系高振转激发态的跃迁结构,为急需VN分子内部结构的其他研究领域提供了重要的结构信息. 从这些公式出发,我们定义了表征实验测定谱线对新谱线的贡献度C（contribution）参数,进一步分析了高激发振转跃迁谱线的相互依赖关系,结果表明该物理公式不仅很好地复现了已知的实验数据,正确地预言了实验未能测定的高激发振转跃迁谱线,而且还能了解不同实验谱线对新谱线的贡献程度,基于这些贡献度,实验学家可以将有限的资源更好地进行分配,重点研究那些贡献度大的振转跃迁谱线. 关键词： 双原子分子 跃迁谱线 贡献度 VN     

Theoretical analysis of collisional shift and broadening of antiprotonic helium spectral lines

Effect of medium density on shift and broadening of ( ) spectral lines is considered in the framework of binary-collision approximation with an effective ( )–He potential including the long-range attraction and short-range repulsion. Quantum calculations of the scattering phase shifts at reasonable values of the potential parameters allow to explain the main features of the observed density effect on the shape of ( ) spectral lines in low-temperature helium. This revised version was published online in August 2006 with corrections to the Cover Date.     

Stark broadening of In III, Tb III, and Pb IV spectral lines

Using a semiclassical approach, the authors consider the widths and shifts of spectral lines for twenty In III and two Tl III multiplets initialed by collisions with electrons, protons, and ions of helium at a density of the perturbing particles of 10¹⁷ cm⁻³ and temperatures from 20,000 to 500,000 K. For two Pb IV multiplets, the widths and shifts of spectral lines produced by collisions with electrons, protons, and ions of He III at a density of the perturbing particles of 10¹⁷ cm⁻³ and temperatures from 50,000 to 1,000,000 K are considered similarly. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 6, pp. 753–757, November–December, 1999.     

平面晶体谱仪弯曲谱线波长定标方法

为了满足激光等离子体X射线光谱测量的需要,提出了一种利用平面晶体谱仪记录得到的弯曲谱线来进行波长标定的新方法。传统的参考谱线法需要已知两条以上谱线的确切波长才能进行波长标定,而利用弯曲谱线可以在不知道任何谱线信息的情况下进行波长标定。通过对实验中所获得的铝等离子体He自发射谱线弯曲图像的分析,得到在目前所使用的谱仪条件下,该方法的波长定标精度可以达到210-4 nm。     

Correction of the self-absorption for reversed spectral lines: application to two resonance lines of neutral aluminium

A new method for the correction of reversed spectral lines, in consequence of self-absorption, is proposed in this article. This method was applied to two resonance lines of neutral aluminium (Al I) obtained by a laser pulse on an aluminium solid placed in air. Several spectra of these lines were corrected for various delays after the laser pulse. The evolution of several parameters of these lines was computed as a function of this delay after the correction of self-absorption.     

软X射线条纹相机光阴极能谱响应灵敏度

通过对条纹相机光阴极在光电转换过程中光电子产生过程的分析,推导了光阴极在软X射线波段的能谱响应灵敏度计算公式,并运用该公式探讨了阴极厚度、掠入射角度等参数对能谱响应灵敏度的影响,计算并分析了Au,CsI在0.1~10keV范围内的能谱响应曲线和特性,并利用标定试验数据对共识和模型的可靠性进行了验证。结果表明,CsI阴极的最佳厚度在60nm左右,Au阴极的最佳厚度在10nm左右;CsI阴极的能谱响应灵敏度比Au阴极高1~2量级。     

Higher order harmonics suppression in extreme ultraviolet and soft x-ray

The extreme ultraviolet and soft x-ray sources are widely used in various domains. Suppressing higher order harmonics and improving spectral purity are significant. This paper describes a novel method of higher order harmonics suppression with single order diffraction gratings in extreme ultraviolet and soft x-ray. The principle of harmonic suppression with single order diffraction grating is described, and an extreme ultraviolet and soft x-ray non-harmonics grating monochromator is designed based on the single order diffraction grating. The performance is simulated by an optical design software. The emergent beams of a monochromator with different gratings are measured by a transmission grating spectrometer. The results show that the single order diffraction grating can suppress higher order harmonics effectively, and it is expected to be widely used in synchrotron radiation, diagnostics of laser induced plasma, and astrophysics.     

软X射线条纹相机光阴极能谱响应灵敏度

通过对条纹相机光阴极在光电转换过程中光电子产生过程的分析,推导了光阴极在软X射线波段的能谱响应灵敏度计算公式,并运用该公式探讨了阴极厚度、掠入射角度等参数对能谱响应灵敏度的影响,计算并分析了Au,CsI在0.1~10 keV范围内的能谱响应曲线和特性,并利用标定试验数据对共识和模型的可靠性进行了验证。结果表明,CsI阴极的最佳厚度在60 nm左右,Au阴极的最佳厚度在10 nm左右;CsI阴极的能谱响应灵敏度比Au阴极高1~2量级。     

Dirac R-matrix calculations of photoionization cross sections of Ni XII and atomic structure data of Ni XIII

We performed R-matrix calculations for photoionization cross sections of the two ground state configuration 3s²3p⁵ (²P^o_3/2,1/2) levels and 12 excited states of Ni XII using relativistic Dirac Atomic R-matrix Codes (DARC) across the photon energy range between the ionizations thresholds of the corresponding states and well above the thresholds of the last level of the Ni XIII target ion. Generally, a good agreement is obtained between our results and the earlier theoretical photoionization cross sections. Moreover, we have used two independent fully relativistic GRASP and FAC codes to calculate fine-structure energy levels, wavelengths, oscillator strengths, transitions rates among the lowest 48 levels belonging to the configuration (3s²3p⁴, 3s3p⁵, 3p⁶, 3s²3p³3d) in Ni XIII. Additionally, radiative lifetimes of all the excited states of Ni XIII are presented. Our results of the atomic structure of Ni XIII show good agreement with other theoretical and experimental results available in the literature. A good agreement is found between our calculated lifetimes and the experimental ones. Our present results are useful for plasma diagnostic of fusion and astrophysical plasmas.     

icMRCI方法研究NS~±离子体系基态光谱

本文采用高精度的内收缩多参考组态相互作用方法(icMRCI)计算了NS~±体系基态的势能曲线,为了能够获得精确结果在计算过程中考虑了能量的Davidson修正.之后基于获得的势能曲线求解核的一维Schr?dinger方程,得到了NS~±离子体系基态的光谱数据R_e、ω_e、ω_eχ_e、B_e、α_e.发现本文理论计算结果与已有的实验数据和现有理论值吻合得很好.并进一步计算了NS~+(X~1Σ~+)基态和NS~-(X~3Σ~-)基态的振动能级G(ν)和体系转动量子数J=0时的分子离心畸变常数B_ν、D_ν.与实验数据和其他理论结果的比较表明本文计算结果达到了较高精度能够为这一离子体系的进一步研究提供参考依据.     

Pressure dependence of the spectral lines of a high power, high pressure atomic fluorine laser pumped by a charge transfer from He2

Various transitions of a pressure tunable atomic fluorine laser have been observed over a rather wide spectral range, 634.8–755.2 nm, by exciting the atmospheric pressure of helium containing 0.2% F₂ in a preionized Blumlein discharge device with a charging voltage of 10–15 kV. The intensity of two quartet transitions, 739.9 and 755.2 nm, increases with pressure, whereas that of the other quartet and doublet lines, 634.8, 641.4, 712.8 and 731.1 nm, decreases with increasing atmospheric fill-pressure. The pumping mechanisms at high pressures appear to be different from those at relatively low pressures.