Concentration measurement of NO using self-absorption spectroscopy of the gamma band system in a pulsed corona discharge

摘要

Nitric oxide (NO) concentrations were measured using the gamma band system spectrum based on the strong self-absorption effect of NO in pulsed corona discharges. The radiative transitional intensities of the NO gamma band were simulated based on the theory of molecular spectroscopy. The intensities of some bands, especially gamma(0, 0) and gamma(1, 0), are weakened by the self-absorption. The correlations between the spectral self-absorption intensities and NO concentration were validated using a modified Beer-Lambert law with a combined factor K relating the branching ratio and the NO concentration, and a nonlinear index alpha that is applicable to the broadband system. Optical emissive spectra in pulsed corona discharges in NO and N_(2)/He mixtures were used to evaluate the two parameters for various conditions. Good agreement between the experimental and theoretical results verifies the self-absorption behavior seen in the UV spectra of the NO gamma bands.