Measurements of line parameters for 12C16O2 near λ = 1.05 μm by cavity ring-down spectrometer

Abstract

The absorption spectra of ¹²C¹⁶O₂ within the wavenumber range of 9358–9648 cm⁻¹ have been precisely measured using a continuous-wave cavity ring-down spectrometer at room temperature. Employing synthetic gas mixtures comprising carbon dioxide, nitrogen, and argon, the line parameters, including line intensities and self-, N₂- and Ar- broadening coefficients have been retrieved in the 2003r-00001 (r = 1,2,3) bands. This retrieval process was facilitated by a multi-spectral fitting program that utilizes Voigt line profiles. A comparative analysis of our measured line intensities and self-broadening coefficients with those present in established databases, such as HITRAN2020, CDSD296, AMES-2021, and HITEMP2010, has been conducted. The line intensities and self-broadening coefficients for ¹²C¹⁶O₂ deviate by an average of less than 1 % from the values reported in the HITRAN2020 database. The J-dependence of N₂- and Ar- broadening coefficients has been investigated by comparing this work with experimental results and theoretical predictions from other vibrational bands. This research offers important experimental references for the improvement of computational models and the exploration of Venus and Mars.