A comparison of theoretical and solar-flare intensity ratios for the Fe XIX X-ray lines

Atomic data consisting of energy levels, gf-values and wavelengths are presented for the Fe XIX 2s22p4-2s22p33s, 2s2-2p33d arrays that give rise to lines in solar-flare and active-region X-ray spectra. Collision strengths and theoretical intensity ratios are given for the 2s22p4-2s22p3 3d lines, which occur in the 13.2-14.3 A range. Solar spectra in this range include a large number of other intense lines, notably those due to He-like Ne (Ne IX). Although the Ne IX lines are potentially the most useful indicators of electron density in solar X-ray spectra, blending with the Fe XIX lines has been a major problem for previous analyses. Comparison of observed spectra with those calculated from the Fe XIX atomic data presented here and Ne IX lines from other work indicates that there is generally good agreement. (author)