On the validity of the ICFT R-matrix method: Fe xiv

G. Del Zanna, N. R. Badnell, L. Fernandez-Menchero, G. Y. Liang, H. E. Mason, P. J. Storey

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Recently, Aggarwal & Keenan published a Dirac R-matrix (darc) calculation for the electron-impact excitation of Fe xiv. A 136-level configuration-interaction/close-coupling (CI/CC) expansion was adopted. Comparisons with earlier calculations, obtained by Liang et al. with the intermediate coupling frame transformation (ICFT) R-matrix method, showed significant discrepancies. One of the main differences was that the Liang et al. effective collision strengths were consistently larger. Aggarwal & Keenan suggested various possible causes for the differences. We discuss them in detail here. We have carried out an ICFT R-matrix calculation with the same 136-level CI/CC expansion adopted by Aggarwal & Keenan, and compared the results with theirs and with those of Liang et al., which employed a much larger CI/CC expansion. We find that the main differences arise because of the different CC and CI expansions, and not because of the use of the ICFT method, as suggested by Aggarwal & Keenan. The significant increase in the effective collision strengths obtained by Liang et al. is mainly due to the extra resonances that are present because of the larger target expansion.
LanguageEnglish
Pages2909-2917
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Volume454
Early online date17 Oct 2015
DOIs
Publication statusPublished - 11 Dec 2015

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matrix methods
matrix
collision
expansion
configuration interaction
electron
collisions
electron impact
method
calculation
causes
excitation
comparison

Keywords

  • atomic data
  • spectroscopic techniques
  • collision strengths

Cite this

Del Zanna, G., Badnell, N. R., Fernandez-Menchero, L., Liang, G. Y., Mason, H. E., & Storey, P. J. (2015). On the validity of the ICFT R-matrix method: Fe xiv. Monthly Notices of the Royal Astronomical Society, 454, 2909-2917. https://doi.org/10.1093/mnras/stv2016
Del Zanna, G. ; Badnell, N. R. ; Fernandez-Menchero, L. ; Liang, G. Y. ; Mason, H. E. ; Storey, P. J. / On the validity of the ICFT R-matrix method : Fe xiv. In: Monthly Notices of the Royal Astronomical Society. 2015 ; Vol. 454. pp. 2909-2917.
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Del Zanna, G, Badnell, NR, Fernandez-Menchero, L, Liang, GY, Mason, HE & Storey, PJ 2015, 'On the validity of the ICFT R-matrix method: Fe xiv' Monthly Notices of the Royal Astronomical Society, vol. 454, pp. 2909-2917. https://doi.org/10.1093/mnras/stv2016

On the validity of the ICFT R-matrix method : Fe xiv. / Del Zanna, G.; Badnell, N. R.; Fernandez-Menchero, L.; Liang, G. Y.; Mason, H. E. ; Storey, P. J.

In: Monthly Notices of the Royal Astronomical Society, Vol. 454, 11.12.2015, p. 2909-2917.

Research output: Contribution to journalArticle

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T1 - On the validity of the ICFT R-matrix method

T2 - Monthly Notices of the Royal Astronomical Society

AU - Del Zanna, G.

AU - Badnell, N. R.

AU - Fernandez-Menchero, L.

AU - Liang, G. Y.

AU - Mason, H. E.

AU - Storey, P. J.

N1 - This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

PY - 2015/12/11

Y1 - 2015/12/11

N2 - Recently, Aggarwal & Keenan published a Dirac R-matrix (darc) calculation for the electron-impact excitation of Fe xiv. A 136-level configuration-interaction/close-coupling (CI/CC) expansion was adopted. Comparisons with earlier calculations, obtained by Liang et al. with the intermediate coupling frame transformation (ICFT) R-matrix method, showed significant discrepancies. One of the main differences was that the Liang et al. effective collision strengths were consistently larger. Aggarwal & Keenan suggested various possible causes for the differences. We discuss them in detail here. We have carried out an ICFT R-matrix calculation with the same 136-level CI/CC expansion adopted by Aggarwal & Keenan, and compared the results with theirs and with those of Liang et al., which employed a much larger CI/CC expansion. We find that the main differences arise because of the different CC and CI expansions, and not because of the use of the ICFT method, as suggested by Aggarwal & Keenan. The significant increase in the effective collision strengths obtained by Liang et al. is mainly due to the extra resonances that are present because of the larger target expansion.

AB - Recently, Aggarwal & Keenan published a Dirac R-matrix (darc) calculation for the electron-impact excitation of Fe xiv. A 136-level configuration-interaction/close-coupling (CI/CC) expansion was adopted. Comparisons with earlier calculations, obtained by Liang et al. with the intermediate coupling frame transformation (ICFT) R-matrix method, showed significant discrepancies. One of the main differences was that the Liang et al. effective collision strengths were consistently larger. Aggarwal & Keenan suggested various possible causes for the differences. We discuss them in detail here. We have carried out an ICFT R-matrix calculation with the same 136-level CI/CC expansion adopted by Aggarwal & Keenan, and compared the results with theirs and with those of Liang et al., which employed a much larger CI/CC expansion. We find that the main differences arise because of the different CC and CI expansions, and not because of the use of the ICFT method, as suggested by Aggarwal & Keenan. The significant increase in the effective collision strengths obtained by Liang et al. is mainly due to the extra resonances that are present because of the larger target expansion.

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KW - spectroscopic techniques

KW - collision strengths

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JO - Monthly Notices of the Royal Astronomical Society

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SN - 0035-8711

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