Line strengths, self-broadening, and line mixingin the 20 0 0 - 01 1 0 „S-P…Q branch of carbon dioxide

Abstract:

Using a difference frequency spectrometer we have measured the Q(2) to Q(38) 2000Ã0110,SÃP transitions of carbon dioxide at 296 K and pressures up to 15 kPa. These low pressure spectrawere analyzed using both the Voigt model, and an empirical line shape that blends together a hardcollision model and a speed dependent Lorentzian profile. The broadening coefficients wereobtained with an accuracy of 1% or better. The low density or first order low pressure line mixingparameters were also determined. We have compared both our measured low pressure line-mixingparameters and the complete band spectrum at high pressures with those predicted by a relaxationmatrix calculated from an EPG fitting law. Spectra at the highest pressures were recorded using boththe difference frequency spectrometer and an FTIR spectrometer, the temperature for the latterexperiments being 303 K. The vibrational band intensity and linear pressure shift of the branch asa whole were also measured. © 2000 American Institute of Physics. @S0021-9606~00!01519-1#