Complete set of broadening coefficients and high-order line-shape parameters for N2-broadened CO2 lines, for temperatures ranging from 100 K to 1000 K

Abstract

Broadening coefficients and high-order line-shape parameters, including the speed dependence of the line width, Dicke narrowing and first-order line-mixing parameters, are predicted for N₂-broadened CO₂ lines over a temperature range from 100 K to 1000 K using requantized molecular dynamics simulations (rCMDS). By employing an intermolecular potential, classical equations of motion, and a requantization procedure, rCMDS enable the calculations of N₂-broadened CO₂ spectra across a wide temperature range without use of any adjustable parameters. For each considered temperature, line-shape parameters were retrieved from fits of the rCMDS spectra using the Voigt, speed-dependent Voigt, and Hartmann-Tran profiles, with first-order line mixing accounted for. The obtained parameters and their temperature dependences were compared with experimental data at various temperatures showing excellent agreements. We demonstrate that parameters and their temperature dependences obtained at Earth’s atmospheric temperatures cannot be used to deduce with accuracy those at higher temperatures, relevant for studies of exoplanetary atmospheres and combustion media. Comparisons with databases show that several parameters and their temperature dependences need to be updated by incorporating accurate high-temperature data to correctly simulate the absorption spectra of N₂-broadened CO₂ from low to high temperatures.