Towards improved spectroscopic applications in multi-gas environments: CO2 spectral line parameter measurement and analysis.

The ν1 + 2ν2 + ν3 band of 12CO2 is dominated by weak absorption lines near 2.0 uμm, which has potential application in planetary atmosphere, astrophysical, and hydrocarbon fuel combustion investigations. High-quality spectral line parameters are the foundation of spectroscopic technology. In this work, high-resolution infrared spectra of CO2 were recorded over 5005-5008 cm-1 range using a Distributed Feedback (DFB) laser with a linewidth of Δν < 0.0001 cm-1. H2-, N2-, O2-, Ar-, air- and CO2- line-intensity, collision broadening coefficients, pressure shift coefficients were determined for CO2 transitions R44e, R46 e, R48 e, R50 e at room temperature. Voigt and Rautian profiles were utilized to retrieve the measured line shape of each individual transition at various pressures. The new data extend and complement previous measurements over the target spectral region. In addition, a comprehensive analysis of the measured spectral line shape parameters is conducted to elucidate the characteristics of spectral line intensity, broadening, and pressure-induced shift coefficients under different molecular collision conditions. This has the potential to be valuable for modeling spectral calculations of multi-component systems, optimizing multi-gas environmental spectral calculation, and developing new spectral diagnostic methods.