Ammonia line strengths and N2-, O2-, Ar-, He-, and self-broadening coefficients in the v 2 band near 10.4 µm

Highlights: • Ammonia line strength measurements in the v₂ fundamental band near 10.4 µm. • NH₃ broadening coefficient measurements due to collisions of N₂, O₂, Ar, He, and NH₃. • Measurements of the temperature-dependence of broadening coefficients up to ~ 1800 K. Scanning-wavelength laser absorption measurements were carried out to determine the line strengths and broadening coefficients due to collisions of N₂, O₂, Ar, He, and NH₃ for 12 ammonia transitions in the Q-branch of the v₂ fundamental band near 10.4 µm. The measurements were conducted at 296 K using a high-resolution quantum cascade laser and span the frequency range of 957.5–963.0 cm⁻¹. The absorption features were fitted with a Voigt profile to obtain the spectroscopic parameters. The temperature-dependence of the Ar-broadening coefficients for two transitions, suitable for high-temperature NH₃ detection, were measured using a shock tube for the temperature range of 921–1767 K. The reported spectroscopic parameters are useful for developing NH₃ detection sensors, especially for high-temperature applications involving chemical reactions.