Improved low-lying energy levels determined from solar coronal forbidden and spin-forbidden lines in the 500 1500 Å range
We list observed parity-forbidden and spin-forbidden lines in the 500 1600 Å range emitted by solar coronal plasmas and derive improved energy levels from their wavelengths. The lines, emitted by astrophysical abundant elements, belong to transitions within the ground configurations of the type ns2npk, for n = 2, 3 and k = 0 5, and between the lowest term of the first excited configuration 2s2pk+1 and the 2s22pk ground configurations for k = 0, 1, 2. For each line we give the newly measured wavelength, and the measured or predicted wavelength from the NIST Atomic Spectra Database (ASD) (which except for a few cases includes the previously reported compilation of Kaufman and Sugar [J. Phys. Chem. Ref. Data 15 (1986) 321]), and the values of the transition probability taken from the ASD and CHIANTI database. The list contains measured wavelengths of 136 lines of which over 100 were not available for the Kaufman and Sugar compilation. In addition we provide energy levels that were derived from the reported lines.