Laboratory Identification of Temperature Diagnostic Si vii and S ix Lines Present in the Solar Coronal Spectra Measured by SUMER/SOHO

The solar coronal spectrum between 500 and 1610 Å and at a height of 21,000 km above the west equatorial limb has recently been recorded by the SUMER instrument on SOHO . Using laboratory spectra obtained with the beam-foil technique, we report the identification of 32 lines observed in this spectrum as 2 s 2 2 p 3 3 s -2 s 2 2 p 3 3 p and 2 s 2 2 p 3 3 p -2 s 2 2 p 3 3 d transitions in Si VII and S IX. Theoretical gA -values and branching ratios for the observed lines, obtained from semiempirical configuration interaction calculations, are also presented. Intensity ratios between the 2 s 2 2 p 4 3 P 1 -2 s 2 2 p 4 1 S 0 forbidden transition and transition from the newly identified high-excitation lines that appear in the same wavelength range are temperature sensitive. Calculations of the intensity ratios between the forbidden line and the high-excitation lines for three temperatures are presented. A comparison between the calculations and some of the SUMER observations is provided.