Knowledge Bank

“For first and second spectra the most recent observations are reported. Current information on the ground states, the known configurations, and the ionization potentials is summarized for both the lanthanides and the actinides. The astrophysical importance of these spectra is stressed, and illustrated particularly by the identifications in the current revision of the Solar Spectrum. The possibility of the presence of one line of Ce III in the sun is suggested. If correct, this is the first evidence of the presence of a third spectrum rare-earth line in this star.”