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Abstract In a recent work on line shape parameters for the H 2 O-H 2 [Renaud et al., Icarus , 306 ,275, 2018] it was shown that this far off-resonance collision system displays strong vibrational dependence. In Renaud et al., calculations were made for bands with one bend or stretch (symmetric or antisymmetric) vibrational quanta exchanged. Water is seen throughout the universe under a vast range of conditions. The needs of the spectroscopic and astrophysics communities include data for water vapor transitions with multiple quanta exchanged. In this work, calculations were made using the Modified Complex Robert-Bonamy (MCRB) formalism for 0–4 vibrational quanta exchanged in the ν 1 , ν 2 , and ν 3 bands, and the 3ν 1 + ν 3 band at 13 temperatures from 200 to 3000 K: calculations for more than 100,000 transitions. From these data, the vibrational dependence of the half-width, line shift, and their temperature dependence are studied as a function of rotational transition. The results show a strong and unusual vibrational dependence. The data were used to develop a prediction routine, which is based on theory [Gamache and Hartmann, JQSRT , 83 , 119, 2004] rather than ad hoc fitting to a polynomial or other forms. The resulting prediction algorithm gives line shape parameters with much lower uncertainty compared to those from J″ average values or polynomial methods. A line file, based on HITRAN2016, was created for remote sensing applications that study H 2 O in hydrogen-rich atmospheres. Highlights • Half-width and line shifts for 100,394 H 2 O transitions broadened by H 2 • Temperature dependence of γ and δ by the Gamache-Vispoel model • Prediction routine for γ and δ and their temperature dependence • Hydrogen-broadened line list for H 2 16O, H 2 18O, and H 2 17O based on HITRAN2016 [ABSTRACT FROM AUTHOR]

A Bruker IFS-120HR Fourier transform spectrometer located at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington was used to record a series of spectra of pure H 2 O and air-broadened H 2 O in the regions of the ν 1 and ν 3 bands (3450–4000 cm −1 ) at different pressures, temperatures and volume mixing ratios of H 2 O in air. Eighteen high-resolution, high signal-to-noise (S/N) ratio absorption spectra were recorded at T = 268, 296 and 353 K using two temperature-controlled absorption cells with path lengths of 9.906(1) and 19.95(1) cm. The resolution of the spectra recorded with the 9.906 cm and 19.95 cm absorption cells was 0.006 and 0.008 cm −1 , respectively. A multispectrum nonlinear least squares fitting technique was employed to fit all the eighteen spectra simultaneously to retrieve 313 accurate line positions, 315 intensities, 229 Lorentz air-broadened half-width and 213 air-shift coefficients and their temperature dependences (136 for air-broadened width and 128 for air-shift coefficients, respectively). Room temperature self-broadened half-width coefficients for 209 transitions and self-shift coefficients for 106 transitions were also measured. Line mixing coefficients were experimentally determined for isolated sets of 10 transition pairs for H 2 O-air and 8 transition pairs for H 2 O-H 2 O using the off-diagonal relaxation matrix element formalism, and 85 quadratic speed dependence parameters were measured. Modified Complex Robert-Bonamy (MCRB) calculations of self-, and air-broadened (from N 2 - and O 2 -broadening) half-width and air-shift coefficients, and temperature dependence exponents of air-broadened half-width coefficients are made. The measurements and calculations are compared with each other and with similar parameters reported in the literature. [ABSTRACT FROM AUTHOR]

A line list of transitions for seven isotopologues of water vapor in the 1100–4100 wavenumber range has been constructed for application to atmospheres rich in CO 2 . The quantum transitions for H 2 16 O, H 2 18 O, H 2 17 O, HD 16 O, HD 18 O, and HD 17 O are from the 2012 HITRAN database (Rothman et al., 2013) and those for D 2 16 O are from the ab initio line list of Shirin et al. (2008). The database was constructed using the best available measured parameters and augmented with theoretical calculations. The half-width, γ , its temperature dependence, n , and the line shift, δ , are for CO 2 as the colliding partner or self-collisions and are determined using the Modified Complex Robert–Bonamy (MCRB) theory. The resulting line list contains 282 557 transitions and is available, in the HITRAN 2012 format, from the corresponding author or from the supplemental information of the journal. [ABSTRACT FROM AUTHOR]

Internal vibrational and rotational partition functions are calculated for nine molecules that are abundant in the terrestrial atmosphere and some are also observed in planetary and exoplanet atmospheres. These molecules are often observed in non-local thermodynamic equilibrium (NLTE) conditions. Calculations are made for all isotopologues of these molecules for which data are available, generally for the temperature range T = 1–5000 K. The methods of calculation of the vibrational and rotational partition functions, Q v and Q r , respectively, the convergence, and the uncertainties for each isotopologue are discussed. Finally, a FORTRAN program, NLTE_TIPS_2021.FOR, to recall the NLTE partition sums is discussed. • Total internal partition sums (TIPS) applicable to Non-Local Thermodynamic Equilibrium (NLTE) conditions are reported. • Calculations are made for 65 isotopologues of 9 molecules important in planetary atmospheres. • NLTE-TIPS are reported from 1 K to a T max that insures the TIPS have converged. • A NLTE-TIPS code and associated files are available in FORTRAN language [ABSTRACT FROM AUTHOR]

Abstract: Total internal partition sums are determined from 65 to 3010K for 13C18O2, 13C18O17O, 12CH3D, 13CH3D, H12C12CD, 13C12CH6, 12CH3 79Br, 12CH3 81Br, 12CF4, H12C12C12C12CH, H12C12C12C14N, H12C12C13C14N, H12C13C12C14N, H13C12C12C14N, H12C12C12C15N, D12C12C12C14N, 14N12C12C14N, 15N12C12C15N, 12C32S, 12C33S, 12C34S, 13C32S, H2, HD, 32S16O, 32S18O, 34S16O, 12C3H4, 12CH3, 12C32S2, 32S12C34S, 13C32S2, and 32S12C33S. These calculations complete the partition sum data needed for additional isotopologues in HITRAN2008 and also extend the partition sums to molecules of astrophysical interest. These data, at 25K steps, are incorporated into a FORTRAN code (TIPS_2011.for) that can be used to rapidly generate the data at any temperature in the range 70–3000K. [Copyright &y& Elsevier]

Abstract: Measurements of water vapor in the atmospheres of Venus or Mars by spectroscopic techniques in the infrared range are being made routinely by instruments onboard the Venus Express and the Mars Reconnaissance Orbiter. The interpretation of these measurements in the 2250–4450cm−1 region is being complicated by the presence of HDO lines absorbing radiation in this region. These spectra cannot be modeled properly because line shape parameters for CO2 broadening (principal gas in these atmospheres) of HDO are not available. Here semi-classical line shape calculations for the HDO–CO2 collision system are made using the Robert–Bonamy formalism for some 2300 rotational band transitions of HDO. From these calculations, the half-width, its temperature dependence, and the line shift are determined to aid in the reduction of the measured spectra. These data will greatly reduce the uncertainty of the reduced profiles from the Venus and Mars measurements and will also allow better estimates of the D/H ratio on these planets. [Copyright &y& Elsevier]

Abstract: Complex Robert–Bonamy (CRB) calculations of the half-width, its temperature dependence, and the line shift have been made for the rotation band transitions of H2 16O for N2 or O2, as the bath molecule. First the atom–atom component of the intermolecular potential was adjusted to reproduce the half-widths of the 22 and 183GHz transition determined by Payne et al. (IEEE Trans. Geosci. Remote Sensing 46 (2007) 3601–3617). Then the line shape parameters were determined at seven temperatures (200, 225, 275, 296, 350, 500, and 700K) for the H2O–N2 and H2O–O2 systems. The air-broadened values were determined at each temperature by the standard method. The half-widths, their temperature dependence, and the line shifts were studied as a function of the rotational quantum numbers. Estimating line shape parameters by scaling from one perturbing gas to another was investigated. The calculations were compared with measurement. [Copyright &y& Elsevier]

Abstract: Ozone resonant features in the rotational band are useful for composition measurements in the stratosphere and upper troposphere. However, the density of ozone features in the long wavelengths often decreases precision of other trace species measurements, especially when insufficient spectral parameters exist. This work presents systematic studies of temperature dependent air-broadened linewidth parameters for ozone. Eighteen new experimental measurements are presented and compared with 57 calculated parameters that cover spectral regions currently probed by the Earth Observing System—Microwave Limb Sounder. Comparisons with previous measurements and similar broadening studies in the infrared wavelengths are made. [Copyright &y& Elsevier]

Abstract: Water vapor in the Earth’s atmosphere is being studied in the 3.2–17.76μm spectral region by the atmospheric infrared sounder (AIRS) on Aqua, the troposphere emission spectrometer (TES) and the high-resolution dynamics limb sounder (HIRDLS) on Aura, both part of the NASA EOS mission. However, the lack of sufficient data on spectral parameters will hamper the prospect of accurate retrievals of temperature and concentration profiles. The spectral parameters for thousands of water vapor transitions are required, which are hard to determine by measurements alone. As reported previously [Can. J. Chem. 82 (2004) 1013–1027], of the 10602 measurements of H2O self-broadening half-widths only 440 intercomparisons with more than 3 data points have estimated uncertainty less than 10%. In this work, we have employed the mean relative thermal velocity approximation of the complex implementation of Robert–Bonamy formalism to obtain the self-broadened half-widths and self-induced line shifts for 5442 water vapor transitions in the 3.2–17.76μm region. The calculations are compared with the measurement database and trends in the half-widths and line shifts are studied. [Copyright &y& Elsevier]

Abstract: Several NASA EOS instruments, the atmospheric infrared sounder (AIRS) on Aqua, and the tropospheric emission spectrometer (TES) and the high-resolution dynamics limb sounder (HIRDLS) on AURA, will be measuring water vapor in the Earth’s atmosphere in the 3.2–17.76μm spectral region. In order to do retrievals of temperature and concentration profiles, the spectral parameters for many thousands of water vapor transitions must be known. Currently the largest uncertainty in these data is associated with the pressure-broadened half-width. To help ameliorate this situation, complex Robert–Bonamy calculations were made to determine N2-, O2-, and air-broadened half-widths and line shifts for 5442 transitions of the principal isotopologue of water vapor for the 11 vibrational bands in this region. The intermolecular potential is a sum of electrostatic terms (dipole–quadrupole and quadrupole–quadrupole), isotropic induction and London dispersion terms, and the atom–atom potential expanded to eighth order. The parameters are adjusted as described in Gamache and Hartmann [J. Quant. Spectrosc. Radiat. Transfer 83 (2004) 119]. Calculations were made at 225 and 296K in order to determine the temperature dependence of the half-widths. When possible the data are compared with measurements. The average percent difference between the measured and calculated half-widths is −1.97, 2.6, and −1.55 for N2-, O2-, and air-broadening of water vapor, respectively. The agreement for the line shifts is less satisfactory. It is clear from this work that the calculations will benefit from a comprehensive adjustment of the intermolecular potential. [Copyright &y& Elsevier]

Laboratory spectroscopic data is essential for the modeling of hot exoplanet atmospheres, since molecules such as methane, a major component of hot-Jupiter-type exoplanet atmospheres, have a complex vibrational energy structure that makes computational predictions difficult at high temperatures for ro-vibrational transitions involving highly excited vibrational sates. To better inform line lists used in radiative transfer modeling, the ro-vibrational spectrum of methane has been recorded in the tetradecad region between 1.7 and 1.65 μm (5880–6060 cm−1) through non-local thermodynamic equilibrium (non-LTE) cavity ringdown spectroscopy (CRDS). Non-LTE conditions, characterized by a low rotational temperature (∼39 K) and a high vibrational temperature (up to 1130 K), have been obtained by hypersonic expansion of a pre-heated mixture of argon and methane in a contoured Laval nozzle. The high vibrational temperature increases the intensity of new hot bands, while the very low rotational temperature greatly simplifies their rotational structure, thus facilitating their identification. A close comparison of the recorded CRDS data to the TheoReTS database reveals both inefficient vibrational relaxation between polyads and efficient vibrational relaxation between vibrational states forming a polyad. These effects result in an overpopulation of the lowest vibrational energy level of each polyad, an effect not widely currently incorporated in non-LTE radiative transfer models. A series of new hot band transitions originating from the pentad and octad polyads were assigned and are provided as a line list for use in future databases. • Vibrationally hot and rotationally cold infrared spectra of CH 4. • Simulation of the non-LTE spectrum of CH 4 based on the TheoReTS database. • Temperature retrieval method of non-LTE methane spectra. • Ro-vibrational relaxation process of methane in a hypersonic jet. • Newly assigned hot band transitions from octad and pentad polyads. [ABSTRACT FROM AUTHOR]

Water can be detected throughout the universe: in comets, asteroids, dwarf planets, the inner and outer planets in our solar system, cool stars, brown dwarfs, and on many exoplanets. Here the focus is on locations rich in hydrogen gas. To properly study these environments, there is a need for the line shape parameters for H 2 O transitions in collision with hydrogen. This work presents calculations of the half-width and line shift, made using the Modified Complex Robert–Bonamy (MCRB) formalism, at a number of temperatures. It is shown that this collision system is strongly off-resonance. For such conditions, the atom–atom part of the intermolecular potential dominates the interaction of the radiating and perturbing molecules. The atom–atom parameters were adjusted by fitting the H 2 O–H 2 measurements of Brown and Plymate (1996). Several techniques were used to extract lines for which there is more confidence in the quality of the data. The final potential yields results that agree with the measurements with ∼0.3% difference and a 5.9% standard deviation. Using this potential, MCRB calculations were made for all transitions in the pure rotation, ν 2 , ν 1 , and ν 3 bands. The structure of the line shape parameters and the temperature dependence of the half-width, as a function of the rotational and vibrational quantum numbers, are discussed. It is shown that the power law model of the T-dependence of the half-width is inadequate over large temperature ranges. [ABSTRACT FROM AUTHOR]

This study reports the results from analyzing a number of high resolution, high signal-to-noise ratio (S/N) spectra in the 2.06-μm spectral region for pure CO 2 and mixtures of CO 2 in dry air. A multispectrum nonlinear least squares curve fitting technique has been used to retrieve the various spectral line parameters. The dataset includes 27 spectra: ten pure CO 2 , two 99% 13 C-enriched CO 2 and fifteen spectra of mixtures of 12 C-enriched CO 2 in dry air. The spectra were recorded at various gas sample temperatures between 170 and 297 K. The absorption path lengths range from 0.347 to 49 m. The sample pressures for the pure CO 2 spectra varied from 1.1 to 594 Torr; for the two 13 CO 2 spectra the pressures were ∼10 and 146 Torr. For the air-broadened spectra, the pressures of the gas mixtures varied between 200 and 711 Torr with CO 2 volume mixing ratios ranging from 0.014% to 0.203%. The multispectrum fitting technique was applied to fit simultaneously all these spectra to retrieve consistent set of line positions, intensities, and line shape parameters including their temperature dependences; for this, the Voigt line shape was modified to include line mixing (via the relaxation matrix formalism) and quadratic speed dependence. The new results are compared to select published values, including recent ab initio calculations. These results are required to retrieve the column averaged dry air mole fraction ( X CO2 ) from space-based observations, such as the Orbiting Carbon Observatory-2 (OCO-2) satellite mission that NASA launched in July 2014. [ABSTRACT FROM AUTHOR]

Abstract: Complex Robert–Bonamy calculations of the pressure-broadened half-width and the pressure-induced line shift are made for some 4000 transitions in the ν 3 band of methane with N2, O2, and air as the perturbing gases. This work focuses on A and F symmetry transitions in the spectral range 2726 to 3200cm−1. More work is needed on the intermolecular potential before calculations can be made for the E-symmetry transitions. The calculations are made at 225 and 296K in order to determine the temperature dependence of the half-width. The calculations are compared with measurements. These data are to support remote sensing of the Earth and Titan atmospheres. [Copyright &y& Elsevier]

Abstract: Nitrogen-broadened water vapor line parameters of the (211)←(000) overtone band transitions in the 818–834nm wavelength region are measured by using a tunable diode laser spectrometer. Water vapor is kept at its saturated vapor pressure at room temperature within a sample cell. Use of a balanced detector and a lock-in amplifier helps to increase the detection efficiency and the signal-to-noise ratio. The collisional broadening coefficients are extracted from the fitting of the experimental data by using a standard Voigt line profile. Collisional half-widths of water vapor lines perturbed by nitrogen are evaluated using the complex-valued implementation of the Robert–Bonamy (CRB) formalism. The rotational wave functions and the energy eigenvalues in the (211) vibrational state of water molecule are assumed on the basis of symmetry properties. Hence the outcome of this work also tests the validity of the theoretical approximations. The experimental data are compared with the corresponding theoretical values and the possible causes of deviation between the two have also been discussed. [Copyright &y& Elsevier]