Astron. Astrophys. Suppl. Ser.
Volume 142, Number 2, March I 2000
|Page(s)||313 - 316|
|Published online||15 March 2000|
Atomic data from the IRON Project
XLI. Electron excitation rates among the 3d2 fine-structure levels of Ca-like Fe VII
School of Science & Mathematics, Sheffield Hallam University, Sheffield S1 1WB, UK
2 Department of Materials Science, Faculty of Engineering, Miyazaki University, Miyazaki 889-21, Japan
3 Department of Applied Mathematics & Theoretical Physics, Queen's University, Belfast BT7 1NN, UK
Accepted: 22 October 1999
Electron excitation collision strengths of 3d2 fine-structure transitions in Ca-like Fe vii are calculated using an R-matrix method, which included the 80 terms arising from the 3d2, 3d4s, 3d4p, 3d4d, 3d4f and 3p53d3 configurations. Extensive autoionizing resonance structures together with channel coupling is therefore explicitly included; relativistic effects are accounted for by a term-coupling transformation. A thermal average is taken to obtain the effective fine-structure collision strength as a function of electron temperature T, for log T(K) = 4.3-6. Open 3p-shell resonances are seen to considerably enhance the background collision strength, by several factors for some of the 3d transitions.
Key words: atomic data
© European Southern Observatory (ESO), 2000