Measurements of Collisional Broadening Coefficients by Infrared Polarization Spectroscopy

Abstract

We present measurements of collisional broadening coefficients, obtained at atmospheric pressure, by polarization spectroscopy. Using tunable single mode laser radiation at ∼2 μm, high-resolution infrared polarization spectra were recorded for CO₂–Ar and CO₂–He binary mixtures. The recorded polarization spectra were fitted with a Lorentzian cubed function form to obtain the broadening coefficients. The full-width at half-maxima (FWHM) collisional broadening rates of CO₂ by Ar and He, for the R14 (12⁰1 ← 00⁰0) line, have been determined to be 0.161 ± 0.018 cm⁻¹ atm⁻¹ and 0.1823 ± 0.0032 cm⁻¹ atm⁻¹ respectively.