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Abstract: More than 19,700 transitions belonging to 11 isotopologues of carbon dioxide have been assigned in the room temperature absorption spectrum of highly 18O enriched carbon dioxide recorded by very high sensitivity CW-Cavity Ring Down spectroscopy between 5851 and 6990cm−1 (1.71–1.43μm). This third and last report is devoted to the analysis of the bands of five 17O containing isotopologues present at very low concentration in the studied spectra: 16O12C17O, 17O12C18O, 16O13C17O, 17O13C18O and 12C17O2 (627, 728, 637, 738 and 727 in short hand notation). On the basis of the predictions of effective Hamiltonian models, a total of 1759, 1786, 335, 273 and 551 transitions belonging to 24, 24, 5, 4 and 7 bands were rovibrationally assigned for 627, 728, 637, 738 and 727, respectively. For comparison, only five bands were previously measured in the region for the 728 species. All the identified bands belong to the ΔP=8 and 9 series of transitions, where is the polyad number (V i are vibrational quantum numbers). The band-by-band analysis has allowed deriving accurate spectroscopic parameters of 61 bands from a fit of the measured line positions. Two interpolyad resonance perturbations were identified. Using the newly measured line positions and those collected from the literature, the global modeling of the line positions within the effective Hamiltonian approach was performed and a new set of Hamiltonian parameters was obtained for the 17O12C18O, 16O13C17O and 17O13C18O isotopologues. For the five studied isotopologues, the effective dipole moment parameters of the ΔP=8 and 9 series were derived from a global fit of the measured line intensities. The obtained results will be used for the improvement of the quality of the line positions and intensities in the most currently used spectroscopic databases of carbon dioxide. [Copyright &y& Elsevier]

The room temperature absorption spectrum of highly 18O enriched carbon dioxide has been recorded by very high sensitivity CW-Cavity Ring Down spectroscopy between 5851 and 6990cm−1 (1.71–1.43μm). The achieved sensitivity (noise equivalent absorption α min ∼5×10−10−5×10–11 cm−1) has allowed the detection of more than 19,000 transitions belonging to eleven isotopologues of carbon dioxide. This first report is devoted to the analysis of the 16O12C18O data. A total of 6452 transitions belonging to 71 bands were rovibrationnally assigned on the basis of the predictions of the effective Hamiltonian model. For comparison, only twelve 16O12C18O bands were previously measured by Fourier Transform spectroscopy in the region. Line intensities of the weakest transitions are on the order of 2×10–29 cm/molecule. The studied spectral region is formed by ΔP=8, 9 and 10 series of transitions, where is the polyad number (V i are vibrational quantum numbers). The band-by-band analysis has allowed deriving accurate spectroscopic parameters of 69 bands from a fit of the measured line positions. A few resonance perturbations were identified. In particular, the 31112 (P=10) and 51105 (P=11) states belonging to different polyads are anharmonically coupled. The resulting intensity transfer leads to the observation of several extra lines of the 51105-01101 hot band which could be assigned. A major result of the present work is the measurement of the ΔP=8 bands of 16O12C18O near 5900cm−1 which are the main responsible of the absorption of carbon dioxide in natural isotopic abundance in the region but are absent in the current version of the CO2 spectroscopic databases (HITRAN, GEISA, and CDSD). These ΔP=8 bands may significantly impact the transmission of CO2 in the 1.70µm transparency window of importance for Venus spectra. Using the large set of newly measured line positions and those collected from the literature, the global modeling of the 16O12C18O line positions within the effective Hamiltonian approach has been performed and a new set of Hamiltonian parameters has been obtained. Using a similar approach, the global fits of the obtained intensity values of the ΔP=8, 9 and 10 series of transitions were used to derive the corresponding set of effective dipole moment parameters. The obtained results will help to improve importantly the quality of the 16O12C18O line positions and line intensities in the most currently used spectroscopic databases of carbon dioxide. [ABSTRACT FROM AUTHOR]

Abstract: The room temperature absorption spectra of nitrous oxide, N2O, have been recorded in the 6950–7653 cm−1 spectral region at 2 and 10Torr using a CW-CRDS spectrometer based on 24 fibered DFB lasers. The achieved sensitivity (noise equivalent absorption α min ≈5×10–11 cm−1) allowed detecting lines with intensities as low as 1×10–29 cm/molecule. In the preceding contribution (Lu Y, Mondelain D, Liu AW, Perevalov VI, Kassi S, Campargue A, J Quant Spectros and Radiat Transfer 2012;113:749–62), we reported the assignment of more than 7200 N2O lines in the region and the derivation of the corresponding spectroscopic parameters G v , B v , D v and H v . In the present work, more than 1300 14N2 16O absolute line intensities of cold and hot bands belonging to the ΔP=12, 13 and 14 series of transitions have been measured (P=2V 1+V 2+4V 3 is the polyad number). The uncertainty of the obtained line intensity values varies from 4 to 7% for the majority of the lines. The obtained dataset extends importantly the set of measurements available in the literature, in particular for the ΔP =13 series for which previous data were very limited. The ΔP=12–14 effective dipole moment parameters were fitted to the intensity values measured in this work and available in the literature. The obtained sets of the dipole moment parameters allow reproducing the observed line intensities within their experimental uncertainties. The calculated intensities of the ΔP=12, 13 and 14 bands of 14N2 16O assigned by CRDS in the 6950–7653 cm−1 region are provided as supplementary material. [Copyright &y& Elsevier]

Abstract: The assignment of the high resolution Fourier transform spectra of carbon dioxide enriched in 17O and 18O which were recorded in LADIR (Paris, France) with the Bruker IFS 125-HR between 1800 and 9000cm−1 and in USTC (Hefei, China) with the Bruker IFS 120-HR between 1700 and 9000cm−1 was performed. In total 239 bands of 12 isotopologues: 16O12C16O, 16O12C18O, 16O13C16O, 16O13C18O, 18O12C18O, 18O13C18O, 16O12C17O, 17O12C17O, 17O12C18O, 16O13C17O, 17O13C17O and 17O13C18O were observed. Among them, 99 bands were observed for the first time. The majority of new observed bands belong to 17OCO isotopologues. The positions of 23,003 lines were determined with the experimental uncertainty on the level of 0.001cm−1. The spectroscopic constants were fitted to the observed line positions for all observed bands. [Copyright &y& Elsevier]