Optical Emission Spectroscopy of Abnormal Glow Discharge in Nitrogen-Methane Mixtures at Atmospheric Pressure

Optical Emission Spectroscopy of Abnormal Glow Discharge in Nitrogen-Methane Mixtures at Atmospheric Pressure

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The abnormal glow discharge was studied in electrode configuration corresponding to gliding arc arrangement with interelectrode gap of 2 mm at the discharge power up to 300 W in nitrogen-methane mixtures (0.5-2.5 % of methane) at atmospheric pressure. Both gases had purity better than 99.999 % and the whole system was evacuated before measurement to suppress oxygen traces. Optical emission spectra were taken in dependence on applied power and gas mixture composition. Nitrogen and CN radical spectra as well as atomic lines of hydrogen and carbon were identified. The vibrational temperatures of 2300-8000 K were determined from the spectra of nitrogen second positive, CN violet and C2 spectral systems. Rotational temperature calculated from nitrogen second positive and CN violet 0-0 bands varied in the interval of 1200-4800 K depending on the experimental conditions.

The abnormal glow discharge was studied in electrode configuration corresponding to gliding arc arrangement with interelectrode gap of 2 mm at the discharge power up to 300 W in nitrogen-methane mixtures (0.5-2.5 % of methane) at atmospheric pressure. Both gases had purity better than 99.999 % and the whole system was evacuated before measurement to suppress oxygen traces. Optical emission spectra were taken in dependence on applied power and gas mixture composition. Nitrogen and CN radical spectra as well as atomic lines of hydrogen and carbon were identified. The vibrational temperatures of 2300-8000 K were determined from the spectra of nitrogen second positive, CN violet and C2 spectral systems. Rotational temperature calculated from nitrogen second positive and CN violet 0-0 bands varied in the interval of 1200-4800 K depending on the experimental conditions.