Atomic data from the IRON project^*

LXIII. Electron-impact excitation of Fe¹⁹⁺ up to n = 4

¹ Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK e-mail: witthoef@phys.strath.ac.uk
² MSSL, University College London, Holmbury St., Mary Dorking, RH5 6NT, UK

Received: 21 November 2006
Accepted: 1 February 2007

Abstract

We present results for the electron-impact excitation of N-like Fe as part of the RmaX network. R-matrix theory using an intermediate-coupling frame transformation method is used to obtain level-resolved collision strengths. Separate calculations are performed using different target expansions. The first is a 215 level close-coupling calculation which has the 2s² 2p³, 2s 2p⁴, 2p⁵, 2s² 2p² 3l, and 2s 2p³ 3l configurations while the second calculation also includes the levels from the 2s² 2p² 4l configurations for a total of 302 close-coupling levels. The effect of the additional resonant enhancement of the larger calculation is explored and compared with a previous IRON Project report and other, more recent, calculations. As a final comparison, we model an astrophysical plasma using the results of the present calculations and previous work.