This study presents a comprehensive spectroscopic investigation of two nitric oxide (NO) absorption transitions (Ω1/2 at 1914.99 cm⁻¹ and Ω3/2 at 1915.76 cm⁻¹) using laser absorption spectroscopy. By employing two complementary experimental systems, namely a continuous flow gas cell for line intensity measurements and a shock tube facility for temperature dependence coefficient characterization, we attained exceptional measurement accuracy with line intensity uncertainties as low as 0.75% while extending the accessible temperature range to 1742 K. The study systematically characterizes temperature dependence coefficients in four buffer gases (Ar, N₂, He, CO₂), revealing distinct gas-specific behaviours, particularly the weak interaction between NO and helium. A rigorous metrological analysis demonstrated substantial improvements in NO quantification accuracy, achieving 13-fold and 3.5-fold uncertainty reductions for scanned-wavelength and fixed-wavelength LAS, respectively. The development of uncertainty mapping and dynamic uncertainty evaluation methodologies further enhanced measurement reliability under transient conditions. These advancements establish new benchmarks for combustion diagnostics, emissions monitoring, and industrial process control, while providing a transferable framework for precision spectroscopy of other molecular species. The comprehensive dataset and methodological innovations presented in this work address critical gaps in high temperature NO spectroscopy and enable more accurate molecular diagnostics in energy, environmental, and industrial applications.
Zhu et al. (Thu,) studied this question.