Collisional-Excitation-Rate Coefficients for Iron Ions Fe viii, Fe ix, and Fe xi

Absolute values of excitation-rate coefficients for Fe viii, Fe ix, and Fe xi were obtained from measurements of relative excitation rates for these ions and the recent measurement of excitation rates for Fe X. With one exception, the results are within a factor of ∼2 of theoretical values. Observed deviations by factors less than 2 are probably not significant because the measurements were done under different plasma conditions and extrapolation of data was needed in their redution.