Buffer-gas pressure broadening at high J values in the v3 band of CO2 measured with tunable diode laser absorption spectroscopy

Pressure broadening coefficients of CO2 perturbed by buffer gases (N-2, O-2, He, and Ar) were studied for four absorption lines R(62), R(64), R(66) and R(68) belonging to the nu(3) band in the 4.2 lm region with tunable diode laser absorption spectroscopy at room temperature for the first time. The broadening coefficients were retrieved by fitting the absorption spectrum with the quadratic speed-dependent Voigt (qSDV) profile. It was shown that the measured broadening coefficients have a behavior of gamma(Ar) < gamma (O-2) < gamma(He) < gamma(N-2). The broadening coefficients by air and Ar were in good agreement with available values in the HITRAN 2016 database and previous measurements in the literature for the same band. (C) 2021 Elsevier Inc. All rights reserved.