The integrated intensities, self- and air-broadening coefficients of thirteen transitions of H216O in the 11980–12260cm−1 region, belonging to the 2ν1+ν2+ν3 band, were measured. Using a tunable diode ...laser system, spectra were recorded at room temperature for a wide range of pressure (2–15Torr for pure H2O and 50–760Torr for H2O in air). Line parameters were adjusted from experiments using three line-shape models: the Voigt profile (VP), the (hard collision) Rautian profile (RP) and the speed dependent Voigt profile (SDVP). The results show that the RP and SDVP are in better agreement with measurements than the VP and that they lead to larger values of the line parameters (about 5% for the line broadening, and 0.8% for the line intensity). Comparisons of the present results with HITRAN 2008 Rothman et al., JQSRT 2009, 110:533-72 show that the HITRAN intensities of the studied lines are overestimated by about 9.4%, suggesting a more complete study of the H2O line parameters in the considered region. The Dicke narrowing and speed dependence parameters deduced from this work are also presented and discussed, demonstrating the need for a more refined line-shape model.
► Spectra of 13 NIR lines of H216O have been measured using a tunable diode laser system. ► Several line shape models have been used to determine the line parameters. ► Intensities and broadenings obtained by the Voigt model are underestimated by 0.8 and 5%. ► The measured intensities are 9% smaller than those in HITRAN 2008 for the studied lines.
•Absorption of CO2 + H2O mixtures is measured in the CO2 4.3 µm band wing.•Determination of the continuum absorption of CO2 due to presence of water vapor.•H2O-continuum of CO2 is significantly ...larger than self-continuum of CO2.•Sub-Lorentzian model for H2O-continuum of CO2 is provided for applications.
In this work, we measured the absorption by CO2 + H2O mixtures from 2400 to 2600 cm−1 which corresponds to the spectral region beyond the ν3 band head of CO2. Transmission spectra of CO2 mixed with water vapor were recorded with a high-resolution Fourier-transform spectrometer for various pressure, temperature and concentration conditions. The continuum absorption by CO2 due to the presence of water vapor was determined by subtracting from measured spectra the contribution of local lines of both species, that of the continuum of pure CO2 as well as of the self- and CO2-continua of water vapor induced by the H2O-H2O and H2O-CO2 interactions. The obtained results are in very good agreement with the unique previous measurement (in a narrower spectral range). They confirm that the H2O-continuum of CO2 is significantly larger than that observed for pure CO2. This continuum thus must be taken into account in radiative transfer calculations for media involving CO2 + H2O mixture. An empirical model, using sub-Lorentzian line shapes based on some temperature-dependent correction factors χ is proposed which enables an accurate description of the experimental results.
•2040 line intensities in the ν2 and ν5 bands of CH3F were measured.•Transition dipole moments squared were derived.•Analysis of the line intensities and transition dipole moments squared were ...performed.•The intensity parameters were retrieved.
Systematic measurements of line intensities in the ν2 and ν5 bands of CH3F were performed for the first time for 2040 transitions using a mono-spectrum fitting technique utilizing a Voigt and Rautian profiles. The spectra are recorded at room temperature for eight pressures of CH3F from 0.1247 to 2.5080 Torr using the Bruker IFS125HR Fourier Transform spectrometer located at the LISA facility in Créteil. Strong intensity perturbations were observed and analyzed accounting for the strong Coriolis coupling ν2 and ν5 bands and l-type interactions in the ν5 band. The transition dipole moments squared were determined for each line, allowing determination of the vibrational transition moment and the Herman–Wallis coefficients of each band using the Aliev and Watson models. Comparison with data available in the literature permits to test the validity of these models applied to the ν2/ν5 dyad system strongly affected by resonances.
•Self-broadening and self-shift coefficients of 510 transitions in the ν1 and ν3 bands of NH3 have been measured at T = 295 K.•The first-order Rosenkranz profile accounting for line-mixing effect was ...adopted to fit the Fourier Transform spectra.•Line-mixing coefficients of 220 lines in the ν1 and ν3 bands of NH3 have been retrieved.•The measured shift coefficients are bipolar.•Line-mixing effects contribute to the observed shift with a quadratic dependence in pressure.
Self-broadening and self-shift coefficients have been measured in the ν1 and ν3 bands of NH3 at room temperature for about 510 ro-vibrational lines with rotational quantum numbers 1 ≤ J ≤ 11. The measurements have been made in numerous branches located in the spectral range from 3050 to 3600 cm−1 using a high-resolution Fourier transform spectrometer. The data have been retrieved using a non-linear least squares multi-pressure fitting procedure of the first-order Rosenkranz profile to eight spectra of NH3. Analysis of the overlapped lines has allowed the measurement of line-mixing parameters for about 200 transitions. The results of pressure broadening coefficients obtained with and without accounting for line-mixing effect have been analyzed as a function of the branches. On average, the accuracies of self-broadening coefficients are estimated to be better than 4%. Those of self-shift and line-mixing are estimated to be about 11% and 17% respectively. About half of the lines have negative shift coefficients with numerous opposite signs for the symmetric and asymmetric doublet components. This work has also shown that line-mixing effects can contribute to the observed shift with a quadratic dependence in pressure.
The whole set of results is given as supplementary material for use in spectroscopic databases.
•Absolute line intensities for the ν4 bands of Trans-HONO and Cis-HONO measured.•Improved line positions using infrared FTS spectra on SOLEIL.•Line list for HONO in the 11 µm infrared region.•For ...cis-HONO, the {41, 51, 61} energy levels are coupled together.
The goal of this work was to update and significantly improve the line lists that have been generated recently for 11 µm bands of the trans- and cis- conformer forms of nitrous acid (HONO) Armante R, Perrin A, Kwabia Tchana F, Manceron L. The ν4 bands at 11 μm: linelists for the trans- and cis- conformer forms of nitrous acid (HONO) in the 2019 version of the GEISA database. Molecular Physics 2021;120:e1951860. That 2019 version of the 11 µm line list was generated using the spectroscopic parameters that were available, at that time, in the literature. During the present study, we used high-resolution Fourier transform spectra recorded at 11 µm to perform a large investigation of line positions and intensities for the ν4 bands of the trans- and cis-conformer of HONO. The resulting set of experimental ν4 (absolute) intensities and of 41 energy levels were used to determine, by least squares fit computations, improved position and intensity parameters for the ν4 bands of the trans- and cis-conformer of HONO. For trans-HONO, the ν4 band appeared not to be perturbed, while for cis-HONO a weak high order B-type Coriolis, coupling together the 41 and 61 energy levels was evidenced for the first time. This new list is of potential interest for the IASI-NG (Infrared Atmospheric Sounding Interferometer - New Generation) instrument which will be launched on board the METOP-SG satellite in 2025.
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In this work, we measured the absorption by CO 2 + H 2 O mixtures from 2400 to 2600 cm −1 which corresponds to the spectral region beyond the ν 3 band head of CO 2. Transmission spectra of CO 2 mixed ...with water vapor were recorded with a high-resolution Fourier-transform spectrometer for various pressure, temperature and concentration conditions. The continuum absorption by CO 2 due to the presence of water vapor was determined by subtracting from measured spectra the contribution of local lines of both species, that of the continuum of pure CO 2 as well as of the self-and CO 2-continua of water vapor induced by the H 2 O-H 2 O and H 2 O-CO 2 interactions. The obtained results are in very good agreement with the unique previous measurement (in a narrower spectral range). They confirm that the H 2 O-continuum of CO 2 is significantly larger than that observed for pure CO 2. This continuum thus must be taken into account in radiative transfer calculations for media involving CO 2 + H 2 O mixture. An empirical model, using sub-Lorentzian line shapes based on some temperature-dependent correction factors χ is proposed which enables an accurate description of the experimental results.
•Collisional broadening and shift coefficients as well as Dicke narrowing parameters of 310 lines in the 2ν4 band of NH3 perturbed by O2 and N2 have been measured at t = 295 K.•Voigt and ...soft-collision Galatry profiles were used to fit the measured line shape of each individual transition at various pressures.•Measurement of narrowing parameters for about 100 transitions of the 2ν4 band.•The measured shift coefficients are linear.•Air-broadening coefficients were retrieved from the linear combination of O2- and N2-broadening coefficients.
Collisional broadening and shift coefficients as well as Dicke narrowing parameters have been measured at room temperature in the 2ν4 band of NH3 perturbed by O2 and N2 for 310 rovibrational lines with rotational quantum numbers 1 ≤ J ≤ 11 and 0 ≤ K ≤ 11.
The experiments were performed at room temperature with ammonia mixtures in nitrogen and oxygen at different pressures using a high-resolution Fourier transform spectrometer and a mono-spectrum non-linear least squares fitting of Voigt and soft-collision Galatry profiles. Because of Dicke narrowing effect, departure from the Voigt profile is observed that allowed measurement of narrowing parameters for about 100 transitions of the 2ν4 band. The collisional broadening coefficients obtained with Galatry profile are larger by about 5% than those derived from Voigt profile. Average absolute accuracies of the measurements are estimated to be 5%, 10% and 14% for broadening, shift and narrowing coefficients, respectively.
Air-broadening coefficients were retrieved from the linear combination of O2- and N2-broadening coefficients. The results are in good agreement with previous experimental data available in the literature. The whole set of results is given as supplementary material for a possible use in spectroscopic databases.
Using Fourier transform spectrometer, He-broadening coefficients in the
and
bands of carbonyl sulfide (
16
O
12
C
32
S) have been measured for the first time in the P- and R-branches. Measurements ...have been performed at room temperature (295 K) for 200 ro-vibrational lines with rotational quantum number ranging from 1 ≤ J ≤ 64, using a mono-spectrum non-linear least squares fitting of Voigt profiles. The measured values were discussed as a function of the rotational quantum number and compared to previous data. These broadening coefficients were also calculated on the basis of Robert and Bonamy's formalism using an ab-initio potential energy surface (PES). In addition, we have measured pressure shift coefficients for 92 transitions in both bands, these results were compared with those of the 2ν
3
band. The line intensities in the
and
bands were also retrieved using the same spectra. The analysis of these intensities allows us to derive a consistent set of line intensity parameters such as vibrational transition moments, band intensities as well as Herman-Wallis (HW) coefficients.
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