Radiative rates and electron impact excitation rate coefficients for Ne-like selenium, Se XXV

Wang, K.; Chen, C.Y.; Huang, Min; Wang, Y.S.; Zou, Yaming

doi:10.1016/j.adt.2011.03.004

Cited by 9 publications

(6 citation statements)

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“…In general, the interference effects, for instance, between resonances or between resonances and continua, are ignored in the IPIRDW approximation. However, the method gives results in good agreement with those from R-matrix for most of the highly charged ions (Gu 2004;Chen et al 2010;Wang et al 2010Wang et al , 2011. More importantly, various physical processes can be taken into account separately in the IPIRDW approach, which facilitates studying their contributions.…”

Section: Introductionmentioning

confidence: 53%

“…As discussed in our recent work (Shen et al 2007a(Shen et al ,b, 2009Zhang et al 2009;Chen et al 2010;Wang et al 2011Wang et al , 2012Li et al 2015), when we use different approaches to include the radiative decay processes of the autoionizing state d, the calculated Auger decay branching ratio B RE d j and the subsequent RE rate coefficients will differ. When we disregard all the radiative transitions, as is done in our small-scale calculation in Sect.…”

Section: Large-scale Ipirdw Resultsmentioning

confidence: 99%

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Electron impact excitation for He-like ions withZ= 20–42

Wang

et al. 2017

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Aims. Spectral lines of He-like ions are among the most prominent features in X-ray spectra from a large variety of astrophysical and high-temperature fusion plasmas. A reliable plasma modeling and interpretation of the spectra require a large amount of accurate atomic data related to various physical processes. In this paper, we focus on the electron-impact excitation (EIE) process. Methods. We adopted the independent process and isolated resonances approximation using distorted waves (IPIRDW). Resonant stabilizing transitions and decays to lower-lying autoionizing levels from the resonances are included as radiative damping. To verify the applicability of the IPIRDW approximation, an independent Dirac R-matrix calculation was also performed. The two sets of results show excellent agreement. Results. We report electron impact excitation collision strengths for transitions among the lowest 49 levels of the 1snl(n ≤ 5, l ≤ (n − 1)) configurations in He-like ions with 20 ≤ Z ≤ 42. The line ratios R and G are calculated for Fe XXV and Kr XXXV. Conclusions. Compared to previous theoretical calculations, our IPIRDW calculation treats resonance excitation and radiative damping effects more comprehensively, and the resulting line emission cross sections show good agreement with the experimental observations. Our results should facilitate the modeling and diagnostics of various astrophysical and laboratory plasmas.

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Section: Introductionmentioning

confidence: 53%

Section: Large-scale Ipirdw Resultsmentioning

confidence: 99%

Electron impact excitation for He-like ions withZ= 20–42

Wang

et al. 2017

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“…One can find more details about the RE calculations from (Shen et al 2007a(Shen et al ,b, 2009Zhang et al 2009;Chen et al 2010;Wang et al 2011Wang et al , 2012.…”

Section: Calculation Procedures and Resultsmentioning

confidence: 99%

“…In our recent work on EIE in H-like Fe 25+ (Chen et al 2010) and other ions (Wang et al 2012(Wang et al , 2011Shen et al 2007aShen et al ,b, 2009Zhang et al 2009), we have extensively studied radiation damping effects due to inclusion of both RS and DAC decays from resonances. It was found that 2pn l resonances could be completely damped out by strong inner 2p−1s RS transitions while n l n l (n > 2) resonances could be significantly damped out by DAC transitions.…”

Section: Discussionmentioning

confidence: 99%

Radiative rates and electron-impact excitation for then≤ 6 fine-structure levels in H-like ions with 13 ≤Z≤ 42

Yan

et al. 2015

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Context. Many observed emission lines from space missions are due to highly charged H-like ions. An analysis of the lines provides information on the temperature, density, and chemical composition of plasmas. A wide range of atomic parameters, such as energy levels, radiative rates, and excitation rate coefficients are needed to achieve this goal. Aims. In this paper we report on calculations for energy levels, radiative rates, collision strengths, and effective collision strengths for transitions among the 36 lowest levels of the n ≤ 6 configurations of highly charged H-like ions with 13 ≤ Z ≤ 42. Methods. The widely used Flexible Atomic Code (FAC) is adopted for the calculation. Energy levels and radiative rates are calculated within the relativistic configuration-interaction method. Employing relativistic distorted-wave approximation, direct excitation collision strengths are calculated at eleven scattered electron energies E f = 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1.0, and 2.5, where E f is in units of Z 2 rydbergs. Collision strengths at higher energies are estimated by interpolation/extrapolation using relativistic Bethe form. 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 independent-process isolated-resonance approximation. Radiation damping effects are taken into account. Results. We present the radiative rates, oscillator strengths, and line strengths for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2), magnetic quadrupole (M2), electric octupole (E3), and magnetic octupole (M3) transitions. Assuming a Maxwellian electron velocity distribution, we report effective collision strengths over a wide temperature range between 2 × 10 3 × Z 2 and 2 × 10 6 × Z 2 K. We believe that the present results are the most extensive and definitive atomic dataset to date for highly charged H-like ions.

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“…Refs. [40,43,56,60] for more details). DE effective collision strengths (Υ) are obtained by integrating collision strengths over a Maxwellian distribution of electron velocities.…”

Section: Ipirdwmentioning

confidence: 99%

Energy levels, transition rates and electron impact excitation rates for B-like Kr XXXII

et al. 2020

Atomic Data and Nuclear Data Tables

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Energy levels and transition rates for electric-dipole, electric-quadrupole, electric-octupole, magnetic-dipole, and magneticquadrupole transitions among the levels arising from the n ≤ 5 configurations in B-like Kr XXXII are calculated by using two state-of-the-art methods, namely, the multi-configuration Dirac-Hartree-Fock (MCDHF) approach and the second-order many-body perturbation theory (RMBPT). Our results are compared with several available experimental and other theoretical values. Electron-impact excitation (EIE) collision strengths are calculated via the independent process and isolated resonance approximation using distorted-wave (denoted by IPIRDW). Radiation damping effects on the resonance excitation contributions are included. Effective collision strengths are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Spectral line intensities are modeled by using collision radiative model, and several line pairs pointed out might be useful for density diagnostics.It is well known that atomic spectroscopy of highly-charged ions is of particular interest for plasma control and plasma diagnostics on chemical composition, electron density and temperature, and electric and magnetic fields. Krypton, as a rare gas, has been widely used in diagnosing tokamak fusion plasmas [1-3], since it does not pollute the vacuum vessel and is easily introduced into the plasmas. Furthermore, due to its almost ideal ionization balance and ease of injection, krypton has been the prime candidate for core Doppler spectroscopy on ITER [4][5][6]. Atomic data (including energy levels, transition rates, collision strengths, etc.) are required for many krypton ions. Recently, we reported accurate level energies, transition parameters and lifetimes for Kr XXIV [7], Kr XXV [8] and Kr XXVII -Kr XXXI [9-13], using both the RMBPT approach and MCDHF method. This work reports our efforts for B-like Kr XXXII.The experimental studies on B-like Kr were very limited [1,2,[14][15][16][17], and only 11 n = 2 levels have been compiled by the Atomic Spectra Database (ASD) of the National Institute of Standards and Technology (NIST) [18]. Most of the existing theoretical calculations were confined to the n = 2 and n = 3 configurations [19-28]. Of particular note was the work presented by Aggarwal et al. [26], in which the Flexible Atomic Code (FAC) [29] and GRASP0 package [30] have been adopted to obtain level energies, lifetimes, wavelengths and transition rates for transitions among the lowest 125 levels of the n ≤ 3 configurations. In addition, Aggarwal et al. [31] also adopted the fully relativistic Dirac Atomic R-matrix Code (DARC) of Norrington and Grant to calculate collision strengths and effective collision strengths. Recently, Liang et al. [32] adopted Thomas-Femi-Dirac-Amaldi model potential from AUTOSTRUCTURE (AS) [33] to calculate the energy levels, line strengths and lifetimes for the 204 n ≤ 4 energy levels of several B-like ions including Kr XXXII. Meanwhile, Liang et al. [32] perf...

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Radiative rates and electron impact excitation rate coefficients for Ne-like selenium, Se XXV

Cited by 9 publications

References 57 publications

Electron impact excitation for He-like ions withZ= 20–42

Electron impact excitation for He-like ions withZ= 20–42

Radiative rates and electron-impact excitation for then≤ 6 fine-structure levels in H-like ions with 13 ≤Z≤ 42

Energy levels, transition rates and electron impact excitation rates for B-like Kr XXXII

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