FE XVI LINE RATIOS IN THE SUN

Recent R-matrix calculations of electron impact excitation rates in Fe XVI are used to derive the emmission-line ratios R(1) = I(251.07 Angs trom)/I(335.40 Angstrom), R(2) = I(262.98 Angstrom)/I(335.40 Angstrom) , and R(3) = I(265.00 Angstrom) /I(335.40 Angstrom). A comparison of t hese with solar observational data obtained by the Naval Research Labo ratory's S082A slitless spectrograph on board Skylab reveals generally good agreement between theory and observation, which provides experim ental support for the accuracy of the atomic data adopted in the analy sis. However, several of the measured ratios are much larger than theo ry predicts, which is probably due to saturation of the strong 335.40 Angstrom line on the photographic film used to record the S082A data. The potential usefulness of R(1), R(2), and R(3) as electron temperatu re diagnostics for the solar corona is briefly discussed.