Experimental Study of Temperature-Dependence Laws of Non-Voigt Absorption Line Shape Parameters

Abstract

To improve the understanding of temperature-dependence laws of spectral line shape parameters, spectra of the v3 rovibrational band of CO2 perturbed by 10, 30, 100, 300 and 1000 mbar of N2 were measured at nine temperatures between 190 K and 330 K using a 22 cm long single-pass absorption cell in a Bruker IFS125 HR Fourier Transform spectrometer. The spectra were fitted employing a quadratic speed-dependent hard collision model in the Hartmann-Tran implementation extended to account for line mixing in the Rosenkranz approximation by means of a multispectrum fitting approach developed at DLR. This enables high accuracy parameter retrievals to reproduce the spectra down to noise level and we will present the behavior of line widths, shifts, speed-dependence-, collisional narrowing- and line mixing-parameters over this 140 K temperature range.