Measurements of spectroscopic parameters of CO2 transitions for Voigt, Rautian, Galatry and speed-dependent Voigt profiles near 1.43 μm using the WM-DAS method

摘要： Linestrengths, self-broadening and narrowing coefficients for 8 absorption transitions of CO2 near 1.43 μm were measured using the wavelength modulation direct absorption spectroscopy (WM-DAS) at 300-1000 K and 5-20 kPa. The SNR was enhanced to 1500 for the peak absorbance around 5% at room temperature and remains at 550 for the peak absorbance around 1% at high temperatures by use of the WM-DAS method. The Voigt, Rautian, Galatry and quadratic speed-dependent Voigt profiles were used to recover the absorbance and retrieve the best-fit spectroscopic parameters and their temperature dependence. The quadratic speed-dependent Voigt profile was found to give the best combination of accuracy and robust lineshape parameters. The measured linestrengths and self-broadening coefficients compare well with the available values listed in the HITRAN/HITEMP database. The self-narrowing coefficients were also determined for GP, RP and qSDVP with analyses of the uncertainties in these spectroscopic parameters.