Abstract
Two-photon absorption laser-induced fluorescence (TALIF) has proven to be a convenient diagnostic for reactive light atoms in plasmas. We have carried out a series of TALIF experiments and report the first temperature measurements of ground state H atoms in an rf discharge. With reasonable care, measurements of the H atom linewidths, broadened by the Doppler effect, provide detailed information about the translational energy, i.e., temperature of the atoms. It is found that in pure H2 plasmas, the H atom temperature is slighthy elevated with respect to ambient. In plasmas contaminated with the other H-containing molecules, Doppler-broadened linewidths corresponding to H atom temperatures in excess of 7000 K have been observed. The mechanisms leading to such high apparent temperatures are discussed.
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Dunlop, J.R., Tserepi, A.D., Preppernau, B.L. et al. H atom plasma diagnostics: A sensitive probe of temperature and purity. Plasma Chem Plasma Process 12, 89–101 (1992). https://doi.org/10.1007/BF01447946
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DOI: https://doi.org/10.1007/BF01447946