Rate coefficients for electron impact excitation of <b>
            
S xv
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Kimura, E.; Nakazaki, Shinobu; Eissner, W.; Itikawa, Yukikazu

doi:10.1051/aas:1999386

Cited by 7 publications

(9 citation statements)

References 10 publications

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“…As mentioned in the introduction, some groups (Zhang and Sampson 1987, Pradhan 1985, Keenan et al 1987, Norrington et al 1998, Kimura et al 1999 reported effective collision strengths for S 14+ , Ca 18+ and Fe 24+ . A comparison is made between the present and the previous results.…”

Section: Resultsmentioning

confidence: 97%

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Rate coefficients for electron impact excitation of helium-like ions within the DiracR-matrix approach

Kimura

Nakazaki

Berrington

et al. 2000

J. Phys. B: At. Mol. Opt. Phys.

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The Dirac R-matrix theory is used to calculate the collision strengths for electron impact excitation of He-like ions (S 14+ , Ca 18+ and Fe 24+ ) using the Dirac atomic R-matrix code, which has been developed mainly by Norrington and Grant (Norrington P H and Grant I P 1987 J. Phys. B: At. Mol. Phys. 20 4869). The lowest 31 target levels are included in the calculation. Rate coefficients are obtained for transitions from the ground 1s 2 1 S 0 state to the fine-structure levels of all excited states of 1s2 ( = 0, 1) and 1s3 ( = 0, 1, 2) configurations. We compare our results for rate coefficients with the results of previous calculations, and indicate where significant differences arise because of our more accurate representation of resonance and relativistic effects.

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Section: Resultsmentioning

confidence: 97%

“…However, the analysis of the satellite data requires collision data between the fine-structure levels. Kimura et al (1999) made calculations of fine-structure cross sections with the use of termcoupling coefficients to include the intermediate-coupling effects. The calculations are based on those of Nakazaki et al (1993).…”

Section: Introductionmentioning

confidence: 99%

Rate coefficients for electron impact excitation of helium-like ions within the DiracR-matrix approach

Kimura

Nakazaki

Berrington

et al. 2000

J. Phys. B: At. Mol. Opt. Phys.

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“…As has been shown for He-like Fe XXV (Kimura et al 1999, Machado-Pelaez et al 2002 the resonances arising from the complex n = N + 1 have a strong effect on transitions to the complex n = N. Along with the full calculation including all the 31 fine-structure states up to n = 4, we considered a smaller target model, including all 17 levels up to n = 3 to compare the effect of the resonances. Figures 6-8 show the effective collision strengths for transitions from the ground state to the n = 2 levels, as well as transitions among levels of the n = 2 complex, and transitions from the ground level and levels of the n = 2 complex to levels of the n = 3 complex.…”

Section: Effective Collision Strengthsmentioning

confidence: 99%

Novel Precursor for Development of Si–C₂H₄–Si Networks in SiCH for Application as a Low-k Cap Layer beyond 22 nm Nodes

Shimizu

Tajima

Kada³

et al. 2010

Jpn. J. Appl. Phys.

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The primary x-ray diagnostic lines in He-like ions are mainly excited by electron impact from the ground level to the n = 2 levels, but at high temperatures n > 2 levels are also excited. In order to describe the atomic processes more completely, collision strengths are computed for O VII including for the first time all of the following: (i) relativistic fine structure, (ii) levels up to n = 4, and (iii) radiation damping of autoionizing resonances. The calculations are carried out using the Breit-Pauli R-matrix method with a 31-level eigenfunction expansion. Resonance structures in collision strengths are delineated in detail up to the n = 4 thresholds. For highly charged He-like ions radiation damping of autoionizing resonances is known to be significant in certain energy ranges. We investigate this effect in detail and find that while resonances are discernibly damped radiatively as the series limit n → ∞ is approached from below, the overall effect on effective cross sections and rate coefficients is found to be very small. Collision strengths for the principal lines important in xray plasma diagnostics, w, x, y and z, corresponding to the four transitions to the ground level 1s 2 ( 1 S 0 ) ←− 1s2p( 1 P o 1 ), 1s2p( 3 P o 2 ), 1s2p( 3 P o 1 ), 1s2s( 3 S 1 ), are explicitly shown. Significant differences are found with previous works for several transitions. The contribution from the resonances converging to the levels from the complex n = 4 is found to be significant for some transitions and can increase the rate by a factor of four. This work is carried out as part of the Iron Project-RmaX Network.

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“…[28] The collision strengths are averaged over a Maxwellian distribution of electron velocities to obtain the effective collision strength. For excitation from initial level i to final level f , the effective collision strength Υ if at electron temperature T e (in Kelvin) is given by [29]…”

Section: Theoretical Methodsmentioning

confidence: 99%

“…Once the effective collision strength is determined, the excitation rate coefficient at electron temperature T e (in Kelvin) is given as [29]…”

Section: Theoretical Methodsmentioning

confidence: 99%

Electron impact excitation rate coefficients of N II ion

et al. 2010

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This paper calculates the electron impact excitation rate coefficients from the ground term 2s22p2 3P to the excited terms of the 2s22p2, 2s2p3, 2s22p3s, 2s22p3p, and 2s22p3d configurations of N II. In the calculations, multiconfiguration Dirac–Fork wave functions have been applied to describe the target-ion states and relativistic distorted-wave calculation has been performed to generate fine-structure collision strengths. The collision strengths are then averaged over a Maxwellian distribution of electron velocities in order to generate the effective collision strengths. The calculated rate coefficients are compared with available experimental and theoretical data, and some good agreements are found for the outer shell electron excitations. But for the inner shell electron excitations there are still some differences between the present calculations and available experiments.

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Rate coefficients for electron impact excitation of S xv

Cited by 7 publications

References 10 publications

Rate coefficients for electron impact excitation of helium-like ions within the DiracR-matrix approach

Rate coefficients for electron impact excitation of helium-like ions within the DiracR-matrix approach

Novel Precursor for Development of Si–C₂H₄–Si Networks in SiCH for Application as a Low-k Cap Layer beyond 22 nm Nodes

Electron impact excitation rate coefficients of N II ion

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Rate coefficients for electron impact excitation of S xv

Cited by 7 publications

References 10 publications

Rate coefficients for electron impact excitation of helium-like ions within the DiracR-matrix approach

Rate coefficients for electron impact excitation of helium-like ions within the DiracR-matrix approach

Novel Precursor for Development of Si–C2H4–Si Networks in SiCH for Application as a Low-k Cap Layer beyond 22 nm Nodes

Electron impact excitation rate coefficients of N II ion

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Novel Precursor for Development of Si–C₂H₄–Si Networks in SiCH for Application as a Low-k Cap Layer beyond 22 nm Nodes