Atomic data for Fe XXII

Intermediate coupling energy levels, oscillator strengths and electron collison strengths in the distorted wave approximation have been computed for Fe XXII. Results are tabulated for the configurations 2s² 2p, 2s 2p², 2s²3s, 2s²3d, 2s 2p 3p, 2s²4s, 2s²4d, 2s 2p 4p. The level population of the excited level in the ground configuration is given as a function of electron density ($$10^{11} -10^{15} cm^{-3}$$) together with theoretical intensity ratios for the strongest transitions from the excited configurations. The theoretical results are compared to available solar flare observations. The intensity ratios observed correspond to electron densities $$\leqslant 10^{13} cm^{-3}$$.