APPLICATION OF HIGH-RESOLUTION FOURIER-TRANSFORM SPECTROMETRY TO THE STUDY OF GLOW-DISCHARGE SOURCES .1. EXCITATION OF IRON AND CHROMIUM SPECTRA IN A MICROWAVE BOOSTED GLOW-DISCHARGE SOURCE

A high-resolution ultraviolet-visible Fourier transform spectrometer h as been used to record spectra from a Grimm-type glow discharge source with and without supplementary microwave excitation. Various cathodes were used (copper, aluminium, iron and chromium) with argon or neon a s the carrier gas. True line profiles were recorded directly, so that line shapes could be studied easily. Close lines could be distinguishe d and identifications made unambiguously, even when major changes in r elative intensities occurred. In this paper, information is presented on the effects of the excitation conditions on the iron and chromium s pectra, using relative intensity measurements on a very large number o f spectral lines. The results emphasize that any 'excitation temperatu res' deduced from data on a limited number of lines are meaningless. T he contribution of charge exchange processes to the excitation of ioni c lines is discussed in detail. Line profile measurements will be repo rted in a subsequent paper.