SI II line ratios in the sun

New atomic data for Si II have been used to predict level populations and emission-line intensity ratios for electron densities and temperatures appropriate to the solar atmosphere. The electron impact collision rates are significantly increased by the presence of complex resonance structure in the low-energy collision strength. Generally good agreement is found with observations obtained from the Naval Research Laboratory slit spectrograph on Skylab. The effect of deviations from a Maxwellian electron energy distribution on the predicted line intensities is also briefly discussed.