Theoretical Emission-Line Strengths for Fe XXIII and a Comparison with Solar Observational Data

Electron impact excitation rates, calculated with a relativistic version of the R-matrix code, are presented for all transitions among the 2s2, 2s2p, and 2p2 levels of Fe XXIII. These data are used to derive theoretical T(e) sensitive emission-line ratios involving Fe XXIII transitions in the 132-1100 A wavelength range. A comparison of our theoretical results for the ratio R1 = I(2s2 1S-2s2p 1P)/I(2s2 1 1S-2s2p 3Pi) = I(132.81 A)/I(263.79 A) with the observed value for a solar flare, obtained with the Goddard Space Flight Center's grating spectrometer on the OSO 5 satellite, reveals good agreement between theory and observation. This provides some experimental support for the accuracy of the atomic data adopted in the line ratio calculations.