A multispectrum fitting procedure to deduce molecular line parameters: Application to the 3-0 band of 12 C 16 O

To deduce accurate infrared molecular line parameters (positions at zero pressure, pressure-shifting and pressure-broadening coefficients, collisional narrowing coefficients, and intensities) from rovibrational spectra, an automatic method based upon a multispectrum fitting procedure has been set up, able to treat simultaneously several laboratory Fourier transform spectra. A validation of this method, using absorption spectra of the 3-0 vibrational band of CO around 6 350 cm^-1, already used to measure line intensities and self-broadening coefficients, is presented, and the advantages of the method are pointed out. The self-collisional narrowing of CO was observed and determined for the first time in Fourier transform spectra: β = 0.028±0.004 cm^-1 atm^-1 at about 296 K. Received 21 September 2000 and Received in final form 15 January 2001