Infrared absorption by pure CO₂ near 3340 cm^-1: Measurements and analysis of collisional coefficients and line-mixing effects at subatmospheric pressures

Abstract

High resolution Fourier transform spectra of the 21102-00001 band of ¹²C¹⁶O₂ near 3340 cm^-1 have been recorded and analyzed to extract isolated-line intensities and collisional parameters, and first-order line-mixing coefficients. Voigt, hard-collision Rautian and Sobel'man, and quadratic-speed-dependent Voigt profiles have been used. The line-mixing coefficients measured for the three branches have also been evaluated using an Energy-Corrected Sudden approach employing a symmetric metric in the Liouville space. These coefficients compare very favorably with the experimental results and estimations with an algorithm available in the literature. Results of straightforward ECS-modeling of complete band shapes have been compared to the recorded spectra and future improvements of this model required at subatmospheric pressures have been outlined.