Electron-ion recombination rate coefficients of Be-like 40Ca16+ 

S. X. Wang, X. Xu, Z. K. Huang, W. Q. Wen, H. B. Wang, N. Khan, S. P. Preval, N. R. Badnell, S. Schippers, S. Mahmood, L. J. Dou, X. Y. Chuai, D. M. Zhao, X. L. Zhu, L. J. Mao, X. M. Ma, J. Li, R. S. Mao, Y. J. Yuan, M. T. Tang & 4 others D. Y. Yin, J. C. Yang, X. Ma, L. F. Zhu

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Electron–ion recombination rate coefficients for beryllium-like calcium ions in the center of mass energy from 0 to51.88 eV have been measured by means of the electron–ion merged-beam technique at the main cooler storage ringat the Institute of Modern Physics in Lanzhou, China. The measurement energy range covers the dielectronicrecombination (DR) resonances associated with the 2s2 1S0  -> 2s2p 3P0,1,2, 1Pcore excitations and the trielectronicrecombination (TR) resonances associated with the 2s2 1S0  -> 2p2 3P0,1,2, 1D2, 1Score excitations. In addition,the AUTOSTRUCTURE code was used to calculate the recombination rate coefficients for comparison with theexperimental results. Resonant recombination originating from parent ions in the long-lived metastable state 2s2p 3Pions has been identified in the recombination spectrum below 1.25 eV. A good agreement is achievedbetween the experimental recombination spectrum and the result of the AUTOSTRUCTURE calculations whenfractions of 95% ground-state ions and 5% metastable ions are assumed in the calculation. It is found thatthe calculated TR resonance positions agree with the experimental peaks, while the resonance strengths areunderestimated by the theoretical calculation. Temperature dependent plasma rate coefficients for DR and TR inthe temperature range of 103–108 K were derived from the measured electron–ion recombination rate coefficientsand compared with the available theoretical results from the literature. In the temperature range of photoionizedplasmas, the presently calculated rate coefficients and the recent results of Gu & Colgan et al. are up to 30% lowerthan the experimentally derived ones, and the older atomic data are even up to 50% lower than the presentexperimental result. This is because strong resonances situated below electron–ion collision energies of 50 meVwere underestimated by the theoretical calculation, which also has a severe influence on the rate coefficients inlow-temperature plasmas. In the temperature range of collisionally ionized plasmas, agreement within 25% wasfound between the experimental result and the present calculation as well as the calculation by Colgan et al. Thepresent result constitutes a set of benchmark data for use in astrophysical modeling.
LanguageEnglish
Number of pages7
JournalAstrophysical Journal
Volume862
Issue number2
Early online date31 Jul 2018
DOIs
Publication statusE-pub ahead of print - 31 Jul 2018

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electron-ion recombination
recombination
electron
ion
coefficients
ions
plasma
temperature
plasma temperature
beryllium
coolers
metastable state
excitation
center of mass
energy
rate
calcium
China
astrophysics
ion beams

Keywords

  • atomic data
  • atomic processes
  • plasmas

Cite this

Wang, S. X., Xu, X., Huang, Z. K., Wen, W. Q., Wang, H. B., Khan, N., ... Zhu, L. F. (2018). Electron-ion recombination rate coefficients of Be-like 40Ca16+ . Astrophysical Journal, 862(2). https://doi.org/10.3847/1538-4357/aacc69
Wang, S. X. ; Xu, X. ; Huang, Z. K. ; Wen, W. Q. ; Wang, H. B. ; Khan, N. ; Preval, S. P. ; Badnell, N. R. ; Schippers, S. ; Mahmood, S. ; Dou, L. J. ; Chuai, X. Y. ; Zhao, D. M. ; Zhu, X. L. ; Mao, L. J. ; Ma, X. M. ; Li, J. ; Mao, R. S. ; Yuan, Y. J. ; Tang, M. T. ; Yin, D. Y. ; Yang, J. C. ; Ma, X. ; Zhu, L. F. / Electron-ion recombination rate coefficients of Be-like 40Ca16+ . In: Astrophysical Journal. 2018 ; Vol. 862, No. 2.
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abstract = "Electron–ion recombination rate coefficients for beryllium-like calcium ions in the center of mass energy from 0 to51.88 eV have been measured by means of the electron–ion merged-beam technique at the main cooler storage ringat the Institute of Modern Physics in Lanzhou, China. The measurement energy range covers the dielectronicrecombination (DR) resonances associated with the 2s2 1S0  -> 2s2p 3P0,1,2, 1P1 core excitations and the trielectronicrecombination (TR) resonances associated with the 2s2 1S0  -> 2p2 3P0,1,2, 1D2, 1S0 core excitations. In addition,the AUTOSTRUCTURE code was used to calculate the recombination rate coefficients for comparison with theexperimental results. Resonant recombination originating from parent ions in the long-lived metastable state 2s2p 3P0 ions has been identified in the recombination spectrum below 1.25 eV. A good agreement is achievedbetween the experimental recombination spectrum and the result of the AUTOSTRUCTURE calculations whenfractions of 95{\%} ground-state ions and 5{\%} metastable ions are assumed in the calculation. It is found thatthe calculated TR resonance positions agree with the experimental peaks, while the resonance strengths areunderestimated by the theoretical calculation. Temperature dependent plasma rate coefficients for DR and TR inthe temperature range of 103–108 K were derived from the measured electron–ion recombination rate coefficientsand compared with the available theoretical results from the literature. In the temperature range of photoionizedplasmas, the presently calculated rate coefficients and the recent results of Gu & Colgan et al. are up to 30{\%} lowerthan the experimentally derived ones, and the older atomic data are even up to 50{\%} lower than the presentexperimental result. This is because strong resonances situated below electron–ion collision energies of 50 meVwere underestimated by the theoretical calculation, which also has a severe influence on the rate coefficients inlow-temperature plasmas. In the temperature range of collisionally ionized plasmas, agreement within 25{\%} wasfound between the experimental result and the present calculation as well as the calculation by Colgan et al. Thepresent result constitutes a set of benchmark data for use in astrophysical modeling.",
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author = "Wang, {S. X.} and X. Xu and Huang, {Z. K.} and Wen, {W. Q.} and Wang, {H. B.} and N. Khan and Preval, {S. P.} and Badnell, {N. R.} and S. Schippers and S. Mahmood and Dou, {L. J.} and Chuai, {X. Y.} and Zhao, {D. M.} and Zhu, {X. L.} and Mao, {L. J.} and Ma, {X. M.} and J. Li and Mao, {R. S.} and Yuan, {Y. J.} and Tang, {M. T.} and Yin, {D. Y.} and Yang, {J. C.} and X. Ma and Zhu, {L. F.}",
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Wang, SX, Xu, X, Huang, ZK, Wen, WQ, Wang, HB, Khan, N, Preval, SP, Badnell, NR, Schippers, S, Mahmood, S, Dou, LJ, Chuai, XY, Zhao, DM, Zhu, XL, Mao, LJ, Ma, XM, Li, J, Mao, RS, Yuan, YJ, Tang, MT, Yin, DY, Yang, JC, Ma, X & Zhu, LF 2018, 'Electron-ion recombination rate coefficients of Be-like 40Ca16+ ' Astrophysical Journal, vol. 862, no. 2. https://doi.org/10.3847/1538-4357/aacc69

Electron-ion recombination rate coefficients of Be-like 40Ca16+ . / Wang, S. X.; Xu, X.; Huang, Z. K.; Wen, W. Q.; Wang, H. B.; Khan, N.; Preval, S. P.; Badnell, N. R.; Schippers, S. ; Mahmood, S.; Dou, L. J.; Chuai, X. Y.; Zhao, D. M.; Zhu, X. L.; Mao, L. J.; Ma, X. M.; Li, J.; Mao, R. S.; Yuan, Y. J.; Tang, M. T.; Yin, D. Y.; Yang, J. C. ; Ma, X.; Zhu, L. F.

In: Astrophysical Journal, Vol. 862, No. 2, 31.07.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Electron-ion recombination rate coefficients of Be-like 40Ca16+ 

AU - Wang, S. X.

AU - Xu, X.

AU - Huang, Z. K.

AU - Wen, W. Q.

AU - Wang, H. B.

AU - Khan, N.

AU - Preval, S. P.

AU - Badnell, N. R.

AU - Schippers, S.

AU - Mahmood, S.

AU - Dou, L. J.

AU - Chuai, X. Y.

AU - Zhao, D. M.

AU - Zhu, X. L.

AU - Mao, L. J.

AU - Ma, X. M.

AU - Li, J.

AU - Mao, R. S.

AU - Yuan, Y. J.

AU - Tang, M. T.

AU - Yin, D. Y.

AU - Yang, J. C.

AU - Ma, X.

AU - Zhu, L. F.

PY - 2018/7/31

Y1 - 2018/7/31

N2 - Electron–ion recombination rate coefficients for beryllium-like calcium ions in the center of mass energy from 0 to51.88 eV have been measured by means of the electron–ion merged-beam technique at the main cooler storage ringat the Institute of Modern Physics in Lanzhou, China. The measurement energy range covers the dielectronicrecombination (DR) resonances associated with the 2s2 1S0  -> 2s2p 3P0,1,2, 1P1 core excitations and the trielectronicrecombination (TR) resonances associated with the 2s2 1S0  -> 2p2 3P0,1,2, 1D2, 1S0 core excitations. In addition,the AUTOSTRUCTURE code was used to calculate the recombination rate coefficients for comparison with theexperimental results. Resonant recombination originating from parent ions in the long-lived metastable state 2s2p 3P0 ions has been identified in the recombination spectrum below 1.25 eV. A good agreement is achievedbetween the experimental recombination spectrum and the result of the AUTOSTRUCTURE calculations whenfractions of 95% ground-state ions and 5% metastable ions are assumed in the calculation. It is found thatthe calculated TR resonance positions agree with the experimental peaks, while the resonance strengths areunderestimated by the theoretical calculation. Temperature dependent plasma rate coefficients for DR and TR inthe temperature range of 103–108 K were derived from the measured electron–ion recombination rate coefficientsand compared with the available theoretical results from the literature. In the temperature range of photoionizedplasmas, the presently calculated rate coefficients and the recent results of Gu & Colgan et al. are up to 30% lowerthan the experimentally derived ones, and the older atomic data are even up to 50% lower than the presentexperimental result. This is because strong resonances situated below electron–ion collision energies of 50 meVwere underestimated by the theoretical calculation, which also has a severe influence on the rate coefficients inlow-temperature plasmas. In the temperature range of collisionally ionized plasmas, agreement within 25% wasfound between the experimental result and the present calculation as well as the calculation by Colgan et al. Thepresent result constitutes a set of benchmark data for use in astrophysical modeling.

AB - Electron–ion recombination rate coefficients for beryllium-like calcium ions in the center of mass energy from 0 to51.88 eV have been measured by means of the electron–ion merged-beam technique at the main cooler storage ringat the Institute of Modern Physics in Lanzhou, China. The measurement energy range covers the dielectronicrecombination (DR) resonances associated with the 2s2 1S0  -> 2s2p 3P0,1,2, 1P1 core excitations and the trielectronicrecombination (TR) resonances associated with the 2s2 1S0  -> 2p2 3P0,1,2, 1D2, 1S0 core excitations. In addition,the AUTOSTRUCTURE code was used to calculate the recombination rate coefficients for comparison with theexperimental results. Resonant recombination originating from parent ions in the long-lived metastable state 2s2p 3P0 ions has been identified in the recombination spectrum below 1.25 eV. A good agreement is achievedbetween the experimental recombination spectrum and the result of the AUTOSTRUCTURE calculations whenfractions of 95% ground-state ions and 5% metastable ions are assumed in the calculation. It is found thatthe calculated TR resonance positions agree with the experimental peaks, while the resonance strengths areunderestimated by the theoretical calculation. Temperature dependent plasma rate coefficients for DR and TR inthe temperature range of 103–108 K were derived from the measured electron–ion recombination rate coefficientsand compared with the available theoretical results from the literature. In the temperature range of photoionizedplasmas, the presently calculated rate coefficients and the recent results of Gu & Colgan et al. are up to 30% lowerthan the experimentally derived ones, and the older atomic data are even up to 50% lower than the presentexperimental result. This is because strong resonances situated below electron–ion collision energies of 50 meVwere underestimated by the theoretical calculation, which also has a severe influence on the rate coefficients inlow-temperature plasmas. In the temperature range of collisionally ionized plasmas, agreement within 25% wasfound between the experimental result and the present calculation as well as the calculation by Colgan et al. Thepresent result constitutes a set of benchmark data for use in astrophysical modeling.

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KW - atomic processes

KW - plasmas

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