A spectroscopic diagnostic method using UV OH band spectrum

Abstract

Noisy and spectrally poorly resolved molecular emission spectra of the 306.357 nm OH band were employed for evaluation of the rotational temperature in different plasma sources, in the temperature range 300 - 6000 K, when an apparatus function of a recording system is unknown. The described method is based on a comparison of experimental data with a theoretical spectrum. The following plasma sources are examined: a recombining jet of plasma torch, an atmospheric pressure glow discharge, a surface ionized wave device and a gliding arc. The temperatures of these weakly ionized plasmas, measured from the OH spectra, are in good agreement with temperatures obtained by using other techniques: thermocouples, tungsten wire resistance measurements and other spectroscopic methods. The results show that the OH spectra are very useful for temperature measurements of non-equilibrium plasmas.