Atomic data from the IRON project - LVI

Electron excitation of Be-like Fe XXIII for the n=2,3,4 configurations

M.C. Chidichimo, G. Del Zanna, H.E. Mason, N.R. Badnell, J.A. Tully, K.A. Berrington

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Collision strengths for electron induced transitions in the beryllium-like ion Fe+22 are calculated using the intermediate coupling frame transformation (ICFT) version of the R-matrix programs. Our target has 98 fine structure states 1 s(2) nl n'l' S LJ corresponding to n = 2 and n' = 2, 3, 4. The present calculation is for electron impact energies in the range 3.15 to 380 Ry. When T exceeds about ten million degrees one needs to take account of contributions to the thermally averaged collision strength Y coming from electrons with energies in excess of 380 Ry. We discuss a way of allowing for these contributions. Values of Y for all the transitions between the ground state and the excited states 1s(2) 2l n l n'l' S' L' J', with n' = 2, 3,4 are tabulated as a function of log T. The temperature range 6.3 less than or equal to log T less than or equal to 8.1 is centred on log T = 7.1 which is approximately where Fe+22 has maximum abundance in ionization equilibrium. To the best of our knowledge these are the first R-matrix calculations for Fe+22 for excitations to the n = 3, 4 levels. Good agreement with previous distored-wave calculations is found. However, the resonance contributions have an important effect on the effective collision strengths and in turn on the level populations.

Original languageEnglish
Pages (from-to)331-341
Number of pages11
JournalExperimental Astronomy
Volume430
Issue number1
DOIs
Publication statusPublished - Jan 2005

Fingerprint

collision
electron
collisions
configurations
excitation
matrix
electrons
beryllium
electron impact
energy
ionization
fine structure
ground state
ion
calculation
project
ions
temperature
effect
programme

Keywords

  • atomic data
  • Sun : corona
  • including N=4 levels
  • collision strengths
  • oscillator strengths
  • impact excitation
  • general program
  • energy levels
  • NI-XXV
  • transition
  • emission
  • lines
  • corona

Cite this

Chidichimo, M.C. ; Del Zanna, G. ; Mason, H.E. ; Badnell, N.R. ; Tully, J.A. ; Berrington, K.A. . / Atomic data from the IRON project - LVI : Electron excitation of Be-like Fe XXIII for the n=2,3,4 configurations. In: Experimental Astronomy. 2005 ; Vol. 430, No. 1. pp. 331-341.
@article{01f4dbd9919040b7aad820535d926a38,
title = "Atomic data from the IRON project - LVI: Electron excitation of Be-like Fe XXIII for the n=2,3,4 configurations",
abstract = "Collision strengths for electron induced transitions in the beryllium-like ion Fe+22 are calculated using the intermediate coupling frame transformation (ICFT) version of the R-matrix programs. Our target has 98 fine structure states 1 s(2) nl n'l' S LJ corresponding to n = 2 and n' = 2, 3, 4. The present calculation is for electron impact energies in the range 3.15 to 380 Ry. When T exceeds about ten million degrees one needs to take account of contributions to the thermally averaged collision strength Y coming from electrons with energies in excess of 380 Ry. We discuss a way of allowing for these contributions. Values of Y for all the transitions between the ground state and the excited states 1s(2) 2l n l n'l' S' L' J', with n' = 2, 3,4 are tabulated as a function of log T. The temperature range 6.3 less than or equal to log T less than or equal to 8.1 is centred on log T = 7.1 which is approximately where Fe+22 has maximum abundance in ionization equilibrium. To the best of our knowledge these are the first R-matrix calculations for Fe+22 for excitations to the n = 3, 4 levels. Good agreement with previous distored-wave calculations is found. However, the resonance contributions have an important effect on the effective collision strengths and in turn on the level populations.",
keywords = "atomic data, Sun : corona, including N=4 levels, collision strengths, oscillator strengths, impact excitation, general program, energy levels, NI-XXV, transition, emission, lines, corona",
author = "M.C. Chidichimo and {Del Zanna}, G. and H.E. Mason and N.R. Badnell and J.A. Tully and K.A. Berrington",
year = "2005",
month = "1",
doi = "10.1051/0004-6361:20041358",
language = "English",
volume = "430",
pages = "331--341",
journal = "Experimental Astronomy",
issn = "0922-6435",
number = "1",

}

Atomic data from the IRON project - LVI : Electron excitation of Be-like Fe XXIII for the n=2,3,4 configurations. / Chidichimo, M.C. ; Del Zanna, G.; Mason, H.E. ; Badnell, N.R. ; Tully, J.A. ; Berrington, K.A. .

In: Experimental Astronomy, Vol. 430, No. 1, 01.2005, p. 331-341.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Atomic data from the IRON project - LVI

T2 - Electron excitation of Be-like Fe XXIII for the n=2,3,4 configurations

AU - Chidichimo, M.C.

AU - Del Zanna, G.

AU - Mason, H.E.

AU - Badnell, N.R.

AU - Tully, J.A.

AU - Berrington, K.A.

PY - 2005/1

Y1 - 2005/1

N2 - Collision strengths for electron induced transitions in the beryllium-like ion Fe+22 are calculated using the intermediate coupling frame transformation (ICFT) version of the R-matrix programs. Our target has 98 fine structure states 1 s(2) nl n'l' S LJ corresponding to n = 2 and n' = 2, 3, 4. The present calculation is for electron impact energies in the range 3.15 to 380 Ry. When T exceeds about ten million degrees one needs to take account of contributions to the thermally averaged collision strength Y coming from electrons with energies in excess of 380 Ry. We discuss a way of allowing for these contributions. Values of Y for all the transitions between the ground state and the excited states 1s(2) 2l n l n'l' S' L' J', with n' = 2, 3,4 are tabulated as a function of log T. The temperature range 6.3 less than or equal to log T less than or equal to 8.1 is centred on log T = 7.1 which is approximately where Fe+22 has maximum abundance in ionization equilibrium. To the best of our knowledge these are the first R-matrix calculations for Fe+22 for excitations to the n = 3, 4 levels. Good agreement with previous distored-wave calculations is found. However, the resonance contributions have an important effect on the effective collision strengths and in turn on the level populations.

AB - Collision strengths for electron induced transitions in the beryllium-like ion Fe+22 are calculated using the intermediate coupling frame transformation (ICFT) version of the R-matrix programs. Our target has 98 fine structure states 1 s(2) nl n'l' S LJ corresponding to n = 2 and n' = 2, 3, 4. The present calculation is for electron impact energies in the range 3.15 to 380 Ry. When T exceeds about ten million degrees one needs to take account of contributions to the thermally averaged collision strength Y coming from electrons with energies in excess of 380 Ry. We discuss a way of allowing for these contributions. Values of Y for all the transitions between the ground state and the excited states 1s(2) 2l n l n'l' S' L' J', with n' = 2, 3,4 are tabulated as a function of log T. The temperature range 6.3 less than or equal to log T less than or equal to 8.1 is centred on log T = 7.1 which is approximately where Fe+22 has maximum abundance in ionization equilibrium. To the best of our knowledge these are the first R-matrix calculations for Fe+22 for excitations to the n = 3, 4 levels. Good agreement with previous distored-wave calculations is found. However, the resonance contributions have an important effect on the effective collision strengths and in turn on the level populations.

KW - atomic data

KW - Sun : corona

KW - including N=4 levels

KW - collision strengths

KW - oscillator strengths

KW - impact excitation

KW - general program

KW - energy levels

KW - NI-XXV

KW - transition

KW - emission

KW - lines

KW - corona

U2 - 10.1051/0004-6361:20041358

DO - 10.1051/0004-6361:20041358

M3 - Article

VL - 430

SP - 331

EP - 341

JO - Experimental Astronomy

JF - Experimental Astronomy

SN - 0922-6435

IS - 1

ER -