Noisy and spectrally not well resolved molecular emission spectra of the 516.611nm Swan band of the C2 molecule were employed for the evaluation of the
rotational temperature in different plasma sources. This diagnostic method may be applied in the temperature range from 300K to 6000K and is specially useful when the
apparatus function of a recording system is unknown The described method is based on a comparison of experimental data with the theoretically calculated spectrum.
Three plasma sources were examined, a plasma torch recombining jet, a high voltage triggered dielectric barrier discharge (DBD), and a RF plasma torch.