All the available data (wave-length measurements and intensity estimates, temperature classes, Zeeman effects) on yttrium lines have been correlated and interpretated in an analysis of the arc and spark spectra. The total number of lines classified is 448 in the Yt I spectrum, 223 in the Yt II spectrum, and 10 in the Yt III spectrum.
No takes yet. Share an insight, caveat, or question.
Meggers et al. (1929) studied this question.