CARS Thermometry of Ethylene Based on Accurate Linewidths

ABSTRACT

Accurate modeling of collisional linewidths is essential for CARS‐based thermometry of complex molecules such as ethylene. In a previous study [JQSRT 234, 24 (2019)], constant isolated‐line widths and empirical temperature scaling were used to model experimental CARS spectra of pure CH over the range 293–804 K, yielding satisfactory agreement but limited physical consistency. Here, we employ specially computed transition‐dependent collisional widths and associated temperature exponents validated on infrared‐absorption measurements to ensure physically meaningful trends and reproduce the experimental spectra with an improved accuracy.