Measurement of temperature-dependent line parameters of ammonia transitions near 1103 cm⁻¹

Accurate knowledge of the line parameters of ammonia (NH₃) transitions is important for developing precise laser-based NH₃ sensors. We report the measurement of line-strengths and temperature-dependent broadening coefficients of NH₃ with N₂, air, Ar, and CO₂ for six transitions in the ν₂ fundamental band near 1103 cm⁻¹. The absorption feature contributed by the target transitions is of particular interest for combustion emission applications due to its strong absorbance and the minimal spectral interference from other species such as H₂O, CO_2, and NO_X. In this work, we measured NH₃ absorption spectra with different collisional partners at the temperature range of 296–573 K using a quantum cascade laser. Spectroscopic parameters were determined by conducting multi-line fitting of the measured spectra using the Galatry lineshape function due to the evident line narrowing effect. Our study will aid the development of mid-infrared NH₃ sensors particularly for high-temperature applications.