Spectroscopic infrared ellipsometry by means of FTS

The use of visible and UV Fourier transform spectrometers for intensity measurement in emission spectra is described. The intensity ratio between different methods of excitation is a useful aid to term analysis: It can be used to confirm an assignment or to indicate an upper state excitation energy. The ratio may be used as a substitute for other confirming data such as the Zeeman effect or hfs. Examples are given from the analysis of Fe I. Illustrative results on line profiles and on continuum observations in the far UV are also presented.