Analysis of the ν3 + ν7 combination band of CF2Cl2 from spectra obtained by high resolution diode laser and FTIR supersonic jet techniquesElectronic supplementary information (ESI) available: line assignments for diode laser spectra for transitions ν3 and ν7 of CF235Cl2 (Table S1) and CF235Cl37Cl (Table S2). See http://www.rsc.org/suppdata/cp/b1/b110919g/

Abstract

High resolution (0.0011 cm À1 full width half maximum) diode laser spectra have been measured for mixtures of CF 2 Cl 2 in Ne, expanded in a supersonic planar jet. In addition interferometric Fourier transform infrared (FTIR) spectra have been recorded with a resolution of about 0.004 cm À1 (FWHM, Hamming apodization) for neat CF 2 Cl 2 , expanded through a circular 200 mm nozzle. We present the analysis of the n 3 + n 7 combination band of CF 2 35 Cl 2 [ñ n 0 ¼ 888.496 89(10) cm À1 ] and CF 2 35 Cl 37 Cl [ñ n 0 ¼ 883.203 89(12) cm À1]. Absolute band strengths have been measured for all bands falling in the atmospheric window (n 3 + n 7 , n 6 , n 1 and n 8 ) and thus being important for monitoring CF 2 Cl 2 in the lower troposphere and stratosphere. A Fermi resonance coupling constant W ¼ (15 AE 2) cm À1 is estimated for the resonance between n 3 + n 7 and n 6 in both isotopomers.

Global CFC-11 (CCl3F) and CFC-12 (CCl2F2) measurements with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS): retrieval, climatologies and trends

“…The spectroscopic uncertainty of this data has been estimated in the literature to be 5 % (Rothman et al, 1998;Rinsland et al, 2005), however the spectral resolution (0.03 cm −1 and 0.01 cm −1 at pressures below 40 Torr, which corresponds to 53.3 hPa) of the laboratory data may introduce small systematic errors, together with the interpolation to different temperatures and pressures. Indeed, CFC-11 and CFC-12 show dense and sharp spectral structure at very high spectral resolution, even in the Q-branches (see, e.g., Orphal, 1991;McNaughton et al, 1994McNaughton et al, , 1995D'Amico et al, 2002). It is also important to note that comparisons of the absolute band intensities (see, e.g., Varanasi and Nemtchinov, 1994;D'Amico et al, 2002) with other studies show larger differences.…”

“…Indeed, CFC-11 and CFC-12 show dense and sharp spectral structure at very high spectral resolution, even in the Q-branches (see, e.g., Orphal, 1991;McNaughton et al, 1994McNaughton et al, , 1995D'Amico et al, 2002). It is also important to note that comparisons of the absolute band intensities (see, e.g., Varanasi and Nemtchinov, 1994;D'Amico et al, 2002) with other studies show larger differences. For these reasons, the absolute uncertainty of the spectroscopic data is estimated to be 10 %, in the absence of further information.…”

High-Resolution Continuous-Wave-Diode Laser Cavity Ring-Down Spectroscopy of the Hydrogen Fluoride Dimer in a Pulsed Slit Jet Expansion: Two Components of the N = 2 Triad near 1.3 μm

“…Early molecular beam spectroscopy was restricted to sensitive molecular beam electric resonance 4 or laser-induced fluorescence detection techniques. − Our group has been involved in developing high-resolution supersonic jet Fourier transform infrared (FTIR) spectroscopy, which has the advantage of covering very broad spectral ranges, still often at the Doppler limit of supersonic jet spectra. − The lower sensitivity of this technique, however, restricts its application to strong absorptions, usually in the fundamental range. The sensitivity can be slightly improved by a combination with diode laser absorption spectroscopy of supersonic jets. − An alternative technique of higher sensitivity is the use of enclosive He-flow cooling instead of supersonic jets …”

“…The sensitivity can be slightly improved by a combination with diode laser absorption spectroscopy of supersonic jets. [11][12][13][14][15][16][17][18] An alternative technique of higher sensitivity is the use of enclosive He-flow cooling instead of supersonic jets. 19 An obvious new technique of high sensitivity is cavity ringdown (CRD) spectroscopy.…”