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• Self-broadening coefficients have been measured in the ν 3 and 2ν 3 -ν 3 bands of CH 3 Cl. • The rotational dependencies of broadening coefficients were analyzed. • The data are modeled using a second-order empirical polynomial. • Broadening coefficients were predicted using the Robert and Bonamy formalism with parabolic and exact trajectory models. • The RBE model is not necessary for calculations of self-broadening of CH 3 Cl even at low temperature. High-resolution Fourier Transform spectra have been recorded at room temperature in the frequency region around 13 µm using a high-resolution Fourier transform spectrometer (Bruker IFS 125-HR). Transitions of both 12CH 3 35Cl and 12CH 3 37Cl isotopologues belonging to the P, Q and R branches of the ν 3 and 2ν 3 -ν 3 parallel bands have been analyzed to retrieve self-broadening coefficients using a multispectrum fitting procedure that allowed to fit simultaneously the whole set of the experimental spectra recorded at seven pressures of CH 3 Cl ranging from 1.02 to 10.24 mbar. Line positions were also derived using a wavenumber calibration performed by the frequencies of OCS transitions. About 2028 lines with 2 ≤ J ≤ 59 and 2 ≤ K ≤ 13 have been studied. The rotational J and K dependencies of the self-broadening coefficients have been clearly observed and modeled using a second-order empirical polynomial. The average accuracy of the line parameters has been estimated to be about 4 and 5% for the ν 3 and 2ν 3 -ν 3 bands, respectively. Using the Robert and Bonamy formalism with parabolic and exact trajectory models, these coefficients were calculated, showing the predominance of the dipole-dipole interaction. The J and K rotational dependencies are consistent with the measured data. The predicted values confirm that the use of the exact trajectory model does not improve the predicted linewidths for a molecule with a large dipole moment such as CH 3 Cl. [ABSTRACT FROM AUTHOR]

• Analysis of Fourier transform spectra of CH 3 I by multispectrum fitting procedure • Measurements of line positions, intensities and self-broadening coefficients • Empirical, semi-empirical and semi-classical calculations of self-widths • Generation of a complete CH 3 I line list of the ν 6 band for atmospheric databases The present work is dedicated to the ν 6 band of 12CH 3 I with the aim of generating a complete line list for databases. High resolution Fourier transform spectra have been recorded in MONARIS and a multispectrum fitting procedure using Voigt profile has been applied to retrieve line positions, intensities, and self-broadening coefficients for around 1200 transitions of the ν 6 band between 854 and 963 cm−1. Rotational dependences of transition dipole moment squared and self-widths have been studied and empirically modeled. Line positions are retrieved with accuracy equal to 4.10−4 cm−1. The accuracy of line intensities and self-widths measurements is estimated between 5 and 10 %. Theoretical estimates of CH 3 I self-broadening coefficients for large ranges of rotational quantum numbers (0 ≤ J ≤ 70, 0 ≤ K ≤ 20) are also provided in the frame of a semi-classical approach with exact trajectories and of a semi-empirical method including a correction factor to the Anderson-type line-width expression. Comparisons of our results with the data previously published in the literature are presented and discussed. A complete line list of 5787 transitions is generated. Available as supplementary material, this line list can be used for spectroscopic databases and atmospheric or industrial detection of CH 3 I. [ABSTRACT FROM AUTHOR]

Several previously unmeasured transitions of 12 CH 3 D have been recorded by a terahertz photomixing continuous-wave spectrometer up to Q R (10) branch at 2.5 THz. An improved set of rotational constants has been obtained utilizing a THz frequency metrology based on a frequency comb that achieved an averaged frequency position better than 150 kHz on more than fifty ground-state transitions. A detailed analysis of the measured line intensities was undertaken using the multispectrum fitting program and has resulted in a determination of new dipole moment parameters. Measurements at different pressures of the Q R (7) transitions provide the first determination of self-broadening coefficients from pure rotational CH 3 D lines. The THz rotational measurements are consistent with IR rovibrational data but no significant vibrational dependence of self-broadening coefficient may be observed by comparison. [ABSTRACT FROM AUTHOR]

• CW-ECDL laser based high-resolution TDLAS spectroscopy of acetylene in 6474–6515 cm−1 spectral region. • First experimental measurement of self-broadening coefficients of approximately 27 l -doublets spectral lines in the p branch of the ν 1 + ν 3 + ν 4 ‒ ν 4 band. • Measurement of line intensities of P -branch transitions of ν 1 + ν 3 + ν 4 ‒ ν 4 band. • Rotational dependency of the self-broadening coefficients have been studied and modelled with third order polynomial. • l -type doubling constants of ν 1 + ν 3 + ν 4 and ν 4 states were determined. Acetylene is considered to be an important molecule for spectroscopic research due to its role in environmental chemistry, astrophysics, biochemistry and photochemistry of various planets. The high resolution spectroscopic studies of acetylene (12C 2 H 2) in the 6474–6515 cm−1 spectral range have been performed using in-house developed external-cavity diode laser absorption spectroscopy technique. The study is focused on experimental measurement of self-broadening coefficients (γ self) and line intensities of 27 l- doublet ro-vibrational lines belonging to the P -branch transition of ν 1 + ν 3 + ν 4 ‒ ν 4 hot band lying in the 6474–6515 cm−1 spectral range. The γ self and line intensity have been retrieved by modelling of each experimentally observed rotational line with standard Voigt line profile using custom written python based computer program. The measured γ self and line intensities were compared with the values present in HITRAN2020 database, showing mean difference of about -1.9% and 2.48%, respectively. In contrast to the line intensity, where rotational and symmetry dependency are readily visible, γ self exhibits only rotational dependency. The l -type doubling constants of both ν 1 + ν 3 + ν 4 and ν 4 states of ν 1 + ν 3 + ν 4 ‒ ν 4 hot band have also been obtained. Detailed understanding of these molecular parameters will play an important role in modelling of planetary atmospheres. [Display omitted] [ABSTRACT FROM AUTHOR]

The 8.5 µm-spectral region of methyl fluoride was studied in terms of line positions, intensities and self-broadening coefficients at room temperature. A multispectrum fitting was used to retrieve from 7 high-resolution Fourier transform spectra line parameters for 787 transitions belonging to the ν 6 band between 1078 and 1240 cm −1 . The accuracy of line intensities and widths measurements were estimated to be around 5% and 5–10% respectively. J - and K -rotational dependences of the transition dipole moment squared and the self-broadening coefficients were observed and modeled from the measurements. A complete line list of almost 1500 transitions was generated for atmospheric or industrial detection of CH 3 F. Comparisons with previous studies from the literature were also performed. [ABSTRACT FROM AUTHOR]

For some temperatures of atmospheric interest from 200 to 298 K, the self-broadening coefficients of OCS-OCS and HCN-HCN collisional systems, at different strengths of electrostatic interactions, were calculated respectively for ν 1 and ν 2 bands for a wide range of rotational quantum numbers J. In particular, we have considered some lines that were not studied previously. We have employed the approximation of bi-resonance functions (Starikov, 2012) in the frame of the semiclassical model of Robert and Bonamy with exact trajectory (RBE). The calculated results are found to be fully consistent with the available experimental values of self-broadening coefficients of OCS and HCN. A comparative study shows that the RBE calculations reproduce the dependence of broadening coefficients on quantum number J much better than the simpler Robert and Bonamy model with parabolic trajectory (RB) for all considered temperatures. [ABSTRACT FROM AUTHOR]

The present report concerns measurements of lines intensities and self-broadening coefficients for 170 transitions of the ν 2 band of both 12 CH 3 35 Cl and 12 CH 3 37 Cl isotopologues between 1291 and 1403 cm −1 . This work is the continuation of a previous effort on the ν 5 band (Barbouchi Ramchani et al., 2013). For these studies, spectra of CH 3 Cl have been recorded at room temperature using a rapid scan Bruker IFS120 HR interferometer. The line parameters have been retrieved using a Voigt profile and a multispectrum fitting procedure. The average accuracy of the line parameters obtained in this work has been estimated to be between 2% and 5% for line intensities and between 5% and 10% for self-broadening coefficients depending on the transitions. A global comparison with the experimental values existing in the literature has been performed. The measurements of line intensities have also been compared to calculated values from HITRAN and GEISA databases. [ABSTRACT FROM AUTHOR]

Relying on high-resolution Fourier transform infrared (FTIR) spectra, the present work involved extensive measurements of individual line intensities and self-broadening coefficients for the ν 7 band of 12 C 2 H 4 . The measured self-broadening coefficients exhibit a dependence on both J and K a . Compared to the corresponding information available in the latest edition of the HITRAN spectroscopic database, the measured line intensities were found to be higher by about 10% for high J lines in the P branch and lower by about 5% for high J lines of the R branch, varying between these two limits roughly linearly with the line positions. The impact of the presently measured line intensities on retrievals of atmospheric ethylene in the 949.0–952.0 cm −1 microwindow was evaluated using a subset of ground-based high-resolution FTIR solar spectra recorded at the Jungfraujoch station. The use of HITRAN 2012 with line intensities modified to match the present measurements led to a systematic reduction of the measured total columns of ethylene by − 4.1 ± 0.1 % . [ABSTRACT FROM AUTHOR]

Abstract: Self-broadening coefficients of transitions belonging to the ν 5 band of methyl chloride have been calculated using a semi-classical model based on the Anderson–Tsao–Curnutte (ATC) theory, including some improvements proposed by Robert and Bonamy. The calculations show the predominance of the dipole–dipole interaction. To better match the experimental measurements performed at room temperature in our previous work, a cut-off of the intermolecular distance has been used. The rotational J and K dependencies of the calculated self-broadening coefficients have been clearly observed and are consistent with our previous measurements. The calculations of the self-broadening coefficients have been performed at various temperatures of atmospheric interest between 200 and 296K in order to deduce the temperature exponent of the self-widths of CH3Cl. [Copyright &y& Elsevier]

Highlights: [•] We have calculated self-broadening and self-shift coefficients using a semi-classical formalism. [•] The calculated coefficients are compared with the set of measurements reported in previous paper. [•] We have studied the different contributions of the potential used in the calculation. [ABSTRACT FROM AUTHOR]

Abstract: High resolution Fourier transform spectra have been recorded around 6.9μm at room temperature using a rapid scan Bruker IFS 120 HR interferometer (unapodized Bruker resolution=0.005cm−1). Transitions of both 12CH3 35Cl and 12CH3 37Cl isotopologues belonging to the ν5 perpendicular band have been studied. Line positions, intensities, and self-broadening coefficients have been retrieved using a multispectrum fitting procedure that allowed to fit simultaneously the whole set of experimental spectra recorded at various pressures of CH3Cl. The wavenumber calibration has been performed using the frequencies of CO2 transitions. The transition dipole moments squared have been determined for each measured line and the whole set of measurements has been compared with previous measurements and with values from HITRAN and GEISA databases. The rotational J and K dependencies of the self-broadening coefficients have been clearly observed and modeled using empirical polynomial expansions. The average accuracy of the line parameters obtained in this work has been estimated to be between 0.1×10−3 and 1×10−3 cm−1 for line positions, between 2% and 5% for line intensities and between 5% and 10% for self-broadening coefficients depending on the transitions. [Copyright &y& Elsevier]

Abstract: A semiclassical impact theory based upon the Anderson–Tsao–Curnutte formalism has been used to calculate the self-broadening coefficients in the P P-, P Q-, P R-, R P-, R Q- and R R-branches of the ν6 band of and near 10μm. Comparisons have then been performed with the extensive set of previous measurements (Jacquemart et al., 2007). The intermolecular potential used, involving the overwhelming electrostatic contributions, leads to larger results than the experimental data for middle J values. By arbitrarily limiting the integration of the differential cross-section to an impact parameter equal to 29Å, quite satisfactory results have been obtained, and the J and K dependences are in reasonable agreement with those observed experimentally. The theoretical results are, on the whole, slightly larger for than for and for same J and K initial states of the transitions they depend on the sub-branch considered. These differences and dependencies were not observed in the previous measurements due to scatter in the experimental data. Finally, the theoretical results obtained for all sub-branches of and are given as supplementary materials of this paper. [Copyright &y& Elsevier]

Abstract: With a diode-laser spectrometer, we have measured self-broadening coefficients of 42 lines of the P-, Q- and R-branches in the ν 4 fundamental band of CH4 at room temperature, with J values ranging between 1 and 12. For the determination of self-broadening parameters, we have fitted to the experimental lineshape two theoretical line profiles: the Voigt profile taking into account Doppler and collisional broadenings, and the hard collision model developed by Rautian and Sobel’man incorporating Dicke narrowing. [Copyright &y& Elsevier]

This work presents a synthesis of our results concerning line intensities and self-broadening coefficients for ClCN in the diad (ν1, 2ν20). Absolute band strengths have been determined. The influence of the perturbation in these band strengths due to a Fermi resonance between the 1000 and 0200 levels has been analyzed. [Copyright &y& Elsevier]

Using FT spectra (unapodized FWHM: 0.002 cm−1) of acetylene 12C2H2, absolute line positions have been measured (average accuracy: ±0.0002 cm−1) between 1860 and 2180 cm−1 in the 3ν51, (2ν4+ν5)1I, and (2ν4+ν5)1II cold bands, improving the wavenumbers previously published by Plı´va under a resolution of about 0.03 cm−1. Absolute intensities have been obtained for more than 130 lines, with a mean accuracy of ±5%, the accuracy of the amount of 12C2H2 in the sample being estimated to be better than 2%. For each band, the vibrational transition dipole moment squared has been determined, as well as empirical Herman–Wallis coefficients. Self-broadening coefficients have been measured at room temperature for more than 120 lines. No striking vibrational dependence has been observed for the self-broadening coefficients, and a polynomial expansion describing the rotational dependence is given. Furthermore, self-shifting coefficients have been measured for 89 lines, together with more than 150 absolute line positions. A multispectrum fitting procedure has been used to retrieve the line parameters from the spectra, and cross comparisons have been performed on a few lines between two different codings of this procedure. [Copyright &y& Elsevier]

Long-pathlength Fourier transform spectra of water vapor recorded previously by Schermaul et al. (J. Mole. Spectrosc.211, 169 (2002)) are analyzed in the range 11 787–13 554 cm−1. Wavenumbers, absolute intensities, and self-broadening coefficients, with associated uncertainties, are presented for 2137 lines. Analysis of these lines using variational linelists has been conducted leading to the assignment of 1906 of the new lines to 23 different upper vibrational states in the 3ν+δ, 4ν, and 4ν+δ polyads, a further 19 lines are ascribed to H218O. Comparisons are made with the HITRAN database. [Copyright &y& Elsevier]

New Fourier transform spectra of water vapor are presented in the range 6500–16 400 cm−1 obtained using pathlengths of up to 800 m and long integration times. These spectra have a significantly higher signal-to-noise than previous measurements in this wavenumber range. Wavenumbers, absolute intensities and self-broadening coefficients, all with associated uncertainties, are presented for 3604 lines in the region 13 200–15 000 cm−1. Analysis of these lines using variational linelists, along with other unassigned lines from previous studies, has been conducted. This leads to 952 new line assignments to transitions involving 35 different vibrational states of H216O. A smaller number of lines are assigned to H218O and H217O. [Copyright &y& Elsevier]

• Calculations of CH 3 I self-broadening coefficients at various temperatures. • Determination of temperature-exponents for line widths. • Deducing double power law parameters. Temperature dependence of methyl iodide self-broadening coefficients in the fundamental ν 6 band is evaluated theoretically by the use of a semi-classical and a semi-empirical approaches in the range 200–400 K recommended for HITRAN. In the absence of not-room-temperature measurements, comparisons are performed solely between line-width sets computed by the two methods at some fixed temperatures. Traditional temperature exponents as well as parameters of the recently suggested double power law JQSRT 2018;217:440-52 (going beyond the considered temperature range) are determined for (J, K)-lines with 0 ≤ J ≤ 70, K ≤ 20 requested by spectroscopic databases. Because of the negligible vibrational dependence, these data can be safely used for other perpendicular and parallel bands studied in atmospheric applications. [ABSTRACT FROM AUTHOR]

• The high-resolution spectra of C 2 H 4 at 1.62 µm are acquired in the temperature range of 296–600 K. • More than 50 lines are recorded in the frequency range 6167.39 to 6177.71 cm−1. • Line positions, line intensities, self-broadening coefficients and its temperature exponent n for those lines are determined by multi-line fitting using Voigt profile. We report the measured line positions, line intensities, self-broadening coefficients and its temperature exponent n of C 2 H 4 for more than 50 lines in the frequency range 6167.39 to 6177.71 cm−1. These spectroscopic parameters were determined by multi-line fitting using the Voigt profile of absorption spectra measured with a distributed-feedback (DFB) tunable diode laser in a well-controlled heated static absorption cell in a temperature range of 296–600 K. The key factors influencing the uncertainties in the determination of the line intensities and self-broadening coefficients were analyzed respectively. To the best of our knowledge, this is the first study that measures the spectrum of C 2 H 4 near 1.62 µm and the line parameters at elevated temperature. [ABSTRACT FROM AUTHOR]