Line-shape parameters and their temperature dependence for self-broadened CO2 lines in the 296 K- 1250 K range by requantized classical molecular dynamics simulations

Abstract

Line-shape parameters for self-broadened CO₂ transitions are predicted for temperatures ranging from 296 K to 1250 K, using requantized molecular dynamics simulations (rCMDS). The line broadening coefficient, the speed dependence component and the first-order line-mixing coefficient for lines with rotational quantum number from 2 to 100, have been determined from fits of the rCMDS spectra with the Voigt and speed dependent Voigt profiles. These parameters and their temperature dependence were compared with recent high-quality measurements at both room and high temperatures, showing good agreements for all considered parameters. In particular, this study highlights that the temperature dependence of the speed dependent Voigt line broadening coefficient in the HITRAN database needs to be corrected. Additionally, we demonstrate that the temperature dependence for the speed-dependence of the line broadening differs from that of the line broadening, contrary to the assumption widely used in the literature. These findings confirm the quality of theoretical predictions using rCMDS. The data provided can be used to complete and improve spectroscopic databases for various applications.