Measurements of CO2 line parameters in the 9250–9500 cm−1 and 10,700–10,860 cm−1 regions

Abstract

The absorption spectra of carbon dioxide have been recorded in two wavenumber ranges 9250–9500cm−1 and 10,700–10,860cm−1 of the near infrared region using a Bruker IFS 125HR Fourier transform spectrometer and a 30m multipass cell with the White type optical system. The spectra were recorded at spectral resolution of 0.03cm−1, room temperature, path length of 726.7m and at four pressures ranging from 187 to 674mbar. The achieved sensitivity (noise equivalent absorption) at the level of kν=7.2×10−10cm−1 allowed detection of numerous new transitions with intensity values down to 5×10−29cm/molecule. The respective measurement time is about 20h. The multispectrum fittings with the Voigt profile were performed to retrieve the line positions and intensities of 12 observed bands. Three hot bands of 12C16O2 in the 9250–9500cm−1 region were detected for the first time. The line intensities of 30032−00001 and 30033−00001 bands of 12C16O2 and of 20032−00001 band of 16O12C18O were measured for the first time.The uncertainty of the line position determination is estimated to be about 0.001cm−1 for the unblended lines with high value of signal-to-noise ratio. The uncertainty of the line intensity determination varies from 5% to 40% depending on the line strength and on extent of line overlapping. The measured line intensities of 30032−00001 and 30033−00001 bands together with those published for the 00051−00001 band were used to fit the effective dipole moment parameters of 12C16O2 for the ΔP=15 series of transitions, where P=2V1+V2+3V3 is a polyad number (Vi (i=1,2,3) are vibrational quantum numbers). The fitted parameters reproduce the measured line intensities within experimental uncertainties. Comparison of the measured line positions and intensities to those contained in HITRAN, GEISA, CDSD and AMES line lists is given.