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A new cryogenic Herriott cell and associated transfer optics have been designed and fabricated at Connecticut College under contract with NASA Langley Research Center to operate for the first time with the broad-band Bruker IFS-125HR Fourier transform spectrometer at the Jet Propulsion Laboratory (JPL). This 0.375 m base-length optical cavity produces an absorption path length, at 293 K, of 20.941 (±0.006) m. The Herriott cell, constructed from oxygen-free high conductivity copper, is placed inside its own vacuum enclosure, which is isolated from the transfer optics chamber by one CaF 2 window and separately evacuated. The transfer optics chamber is in turn coupled to the sample compartment of the Bruker IFS-125HR holding another set of transfer optics. The entire spectrometer, including the transfer optics chamber can be evacuated to ∼10 mTorr; the cell vacuum enclosure is cryogenically evacuated to pressures below 10 −6 Torr. A closed-cycle helium refrigerator cools the Herriott cell. Initially tested at Connecticut College for temperatures between 250 and 50 K, the system has successfully been in operation for over two years at JPL. The cell has been used for recording spectra between 75 and 250 K, achieving excellent temperature uniformity (± 0.15 K) and long term stability (< 0.05 K/day). Configured with a single indium-sealed CaF 2 window, it has provided Doppler-limited infrared absorption spectra of a number of molecular species above 2000 cm −1 to investigate detailed spectroscopic properties (e.g. molecular line parameters at temperatures and pressures relevant to planetary atmospheres). The design, performance and detailed characterization of the Herriott cell system are discussed. [ABSTRACT FROM AUTHOR]

Using a set of gold-coated copper mirrors identical to those reported previously we were able to increase the useful absorption path from 5.9 meters to 12.49 meters. The low temperature performance of the new cell is similar to that of the previously described cell. The testing procedure and results are described here. [ABSTRACT FROM AUTHOR]

Since 1995, Dominica has endured a massive economic downturn following a series of World Trade Organization decisions that have devastated the banana industry, its major export earner. Yet the trade decisions have not been the subject of much anxiety or debate. At the same time, their second largest contributors to foreign exchange earnings (hucksters) are seldom the subject of public discussion. I suggest in this article that these omissions have to do with the manner in which flexibility is culturally conceptualized. Rather than a recent adaptation to the physiopsychological disciplining of a post-Fordian or “globalized” economy, I argue that in Dominica, flexibility is historically constituted through a much longer engagement with capitalism in the formation of the Caribbean as a cultural area over the last five centuries. The entrepreneurial savvy found among hucksters is autochthonous to Dominica's trade culture. [ABSTRACT FROM AUTHOR]

Information on the Seventh International Conference on Tunable Diode Laser Spectroscopy (TDLS-2009), held in Zermatt, Switzerland from July 13-17, 2009, is presented. The meeting discussed the progress made in the development of diode lasers and the application of lasers in research and the real world. A. Lebrun of the International Atomic Energy Agency (IAEA) made a presentation on the status of tunable diode laser spectroscopy contributions to International Safeguards Verification.

Information about several papers discussed at the Sixth International Conference on tunable diode laser spectroscopy that was held in Reims, France on July 9-13, 2007 is presented. The conference include the presentation by Manfred Zendel of the International Atomic Energy Agency (IAEA) entitled "Challenges and Technology Needs" and that of Natacha Peter concerning the applicability of tunable diode laser spectroscopy in addressing international safeguards.

Highlights: [•] Measured 34 spectra of C3H8 at 145–297K from 690 to 1550cm−1 using a FT-IR. [•] Derived cross sections of C3H8 broadened by N2 as a function of temperature. [•] Obtained total intensity of 52.93×10−19 cm−1/(moleculecm−2) at 296K. [•] Also generated ‘pseudo-line list’ which reproduces observed spectra to ±3%. [•] Will support atmospheric remote sensing of Titan, Saturn, and Jupiter. [ABSTRACT FROM AUTHOR]

Abstract: We designed, fabricated and tested a multipath Herriott cell (or off-axis spherical mirror interferometer) to achieve low temperature absorption measurements. The cell is fabricated entirely from copper, and the 15cm radius of curvature copper mirrors have gold coated reflective surfaces. The cell was tested at temperatures between 296 and 20K with a folded absorption path length of 5.37m utilizing a lead salt tunable diode laser. Short term temperature stability (1h) of the Herriott cell is better than 0.005K under normal operating conditions with a temperature uniformity better than 0.01K (not measurable). The cell was tested by performing collisional cooling experiments on 13C16O2 in helium at temperatures between 70 and 20K and by performing more traditional pressure broadening and shift measurements on molecular infrared absorption lines at temperatures between 300 and about 80K on 13C16O2 and methane. [Copyright &y& Elsevier]

Positions and intensities for transitions in the 1←0 bands of the four CO isotopologues ( 12 C 16 O, 13 C 16 O, 12 C 18 O and 13 C 18 O) were retrieved from analyses of spectra of different low-pressure pure samples and high-pressure air-broadened mixtures (1940–2260 cm −1 ) in two different multispectrum fittings involving selected groups of 21 (for 13 C 16 O) and 20 (for 12 C 18 O) spectra. Air-broadened half-width and air-shift coefficients, their temperature dependences, line mixing via off-diagonal relaxation matrix element coefficients for CO-air collision systems, and quadratic speed dependence parameters were measured for 13 C 16 O and 12 C 18 O transitions. In both the fittings, two low-pressure room-temperature spectra of a high purity natural sample of CO recorded with the Kitt Peak FTS were included to retrieve the positions and intensities of 12 C 16 O transitions. All other spectra in the fittings were obtained with either 13 C-enriched or 18 O-enriched samples using the JPL Bruker IFS-125HR FTS. Four absorption cells with path lengths between 0.5131(5) and 20.38(2) cm were used to record the data. The cells are temperature controlled, except for the shortest cell. Positions and intensities for the 1←0 band transitions were determined from the retrieved ro-vibrational constants ( G, B, D and H ), band intensity and Herman-Wallis parameters by applying the theoretical quantum mechanical expressions. The band strengths of 12 C 16 O, 12 C 18 O and 13 C 18 O are very close (∼0.3%) to HITRAN2012 values but for 13 C 16 O the band strength is ∼4.8% larger than the HITRAN2012 and 2.6% larger than the HITRAN2016 value. [ABSTRACT FROM AUTHOR]

In support of infrared remote sensing of Titan, we present temperature dependent cross-sections of propene (C 3 H 6 ; CH 2 CH CH 3 ; propylene) measured in the laboratory. A total of 27 high-resolution (up to 0.0022 cm − 1 ) spectra of pure C 3 H 6 and mixtures of C 3 H 6 with N 2 were obtained at 150–299 K in the 650–1534 cm −1 (6.5–15.4 µm) region. A custom-designed cold cell was used, which was configured with an active temperature control and could be integrated to a Fourier-transform spectrometer (Bruker 125HR) at the Jet Propulsion Laboratory. The observed C 3 H 6 spectral features include its strong v 19 band bearing the most prominent Q-branch peak at 912 cm −1 and three other strong bands: v 18 , v 16 and v 7 centered near 991, 1443, and 1459 cm −1 , respectively. In addition, we have generated empirical pseudoline lists (PLLs) in HITRAN-format, in the two separate spectral regions, which are Region I: 800–1100 and Region II: 1340–1524 cm −1 . The PLLs of C 3 H 6 consists of spectroscopic line parameters (including line intensities and effective lower state energies) for all the individual pseudoline positions. The pseudoline parameters were determined by fitting 27 laboratory spectra of pure and N 2 -broadened propene simultaneously in the selected regions. A newly derived partition function was adopted in the line-by-line radiative transfer calculations. Based on the pseudoline intensities, the total integrated intensities in the 800–1120 and 1320–1524cm −1 regions were measured to be 8.79(47)× 10 −18 and 3.06(21)×10 −18 cm −1 /(molecule cm −2 ) at 296 K, respectively. These values are found to be in a good agreement with the recent measurement made at KAUST at room temperature, but they are significantly lower than those reported by one of the most extensive previous studies at the Pacific Northwest National Laboratory (PNNL). Finally, the two PLLs are submitted as electronic supplements and are also available from the website, https://mark4sun.jpl.nasa.gov/pseudo.html. [ABSTRACT FROM AUTHOR]

A 13 C-enriched spectrum of methane ( 13 CH 4 ) was recorded at Doppler-limited resolution (0.0044 cm −1 ) at 80 K covering the entire Tetradecad region in the 4970–6200 cm −1 . In this paper we present the spectral analysis of the lower part of the 13 CH 4 Tetradecad in the 4970–5470 cm −1 region. Starting with a non-empirical effective Hamiltonian derived by high-order Contact Transformations (CT) from the ab initio potential energy surface (PES), the effective Hamiltonian parameters have been determined for this region by extending the previous DAS (Differential Absorption Spectroscopy) spectral analysis for the upper part of the Tetradecad in the 5853–6200 cm −1 region. In total, 1387 rovibrational transitions were assigned belonging to five cold bands of the Tetradecad up to J max  = 11. Their positions were fitted with an rms deviation of 1.6 × 10 −3 cm −1 . Measured line intensities for 737 transitions were modeled using the effective dipole transition moments approach with an rms deviation of about 10%. Finally, the observed transitions were incorporated to fit simultaneously the 13 CH 4 Hamiltonian parameters for the {Ground state / Dyad / Pentad / Octad / Tetradecad} system and the dipole moment parameters for the {Ground state - Tetradecad} system. [ABSTRACT FROM AUTHOR]

Lorentz half-width coefficients and their temperature dependence exponents for CO 2 broadening in the fundamental bands of HDO are important for reliable and accurate interpretation of Mars and Venus atmospheric data and to determine D/H. Uncertainties in the temperature dependences of the CO 2 -broadened half-width coefficients lead to large errors in the retrieved mixing ratios and hence in HDO column abundances. In this high-resolution FTIR laboratory study, we report first measurements of the temperature dependences of half-width coefficients for HDO transitions in the ν 1 and 2ν 2 bands broadened by CO 2 . Accurate line positions, intensities, CO 2 -broadened width and pressure shift coefficients, their temperature dependences, collisional line mixing coefficients for HDO-CO 2 system and quadratic speed dependence parameters have been retrieved for a large number of transitions in the ν 1 band. Room-temperature self-broadened half-width coefficients, self-shift coefficients, and collisional line-mixing coefficients for HDO-HDO system were also measured for the same number of ν 1 transitions. Positions and intensities were measured for nearly 60 transitions in the weaker 2ν 2 band along with a few room-temperature measurements of CO 2 - and self-broadening and pressure-shift coefficients. These results were obtained from simultaneous nonlinear least squares fittings of ten high-resolution absorption spectra recorded with the Bruker IFS-125HR FTS at JPL and two coolable sample cells. Modified Complex Robert-Bonamy (MCRB) formalism was applied to compute both types of broadening and pressure shift coefficients, and the temperature dependences of the CO 2 - and self-broadening parameters. Present measurements are compared with the MCRB calculations and other theoretical values reported in the literature. [ABSTRACT FROM AUTHOR]

The lack of spectroscopic measurements for rare CO 2 isotopologues was the main motivation of this work. In our present study we report line intensity measurements for 16 O 12 C 17 O made with a high resolution Fourier transform spectrometer (Bruker IFS-125HR) and a 21 m path cryogenic Herriott cell at Jet Propulsion Laboratory. For this, a 17 O-enriched CO 2 gas sample was used, which comes as a mixture of primary and several minor CO 2 isotopologues. The mole fraction of the 16 O 12 C 17 O isotopologue in the mixture was determined to be 0.3991 by mass spectrometry from a Stable Isotope Ratio Mass Spectrometer (SIRMS) under stochastic distribution assumption at thermal equilibrium. Since the collisional narrowing effect was observed, the Rautian molecular line shape profile was systematically adopted instead of the Voigt profile. Absolute line positions were also investigated by performing a wavenumber calibration based on CO, HCl and a few well-known 16 O 12 C 16 O transitions. Finally, around 1000 transitions were studied between 4604 and 5126 cm −1 involving 15 bands of the 16 O 12 C 17 O isotopologue. All the measured line intensities were renormalized to be the values for 100% pure isotopologue sample. Transition dipole moments and Herman-Wallis factors were derived enabling a global comparison with theoretical calculations and predictions for the 15 bands of the 16 O 12 C 17 O isotopologue. For the measured line positions, the absolute accuracy is around 2×10 −4 cm −1 . The accuracies of retrieved line intensities are 2 – 5% for five cold and two hot bands, and 6–30% for eight other weaker hot bands. Results from this work were in a good agreement with HITRAN 2012 for positions, but showed rather significant discrepancies for line intensities. An extensive line list was generated from new experimental measurements in order to improve and validate spectroscopic knowledge of 12 C 16 O 17 O isotopologue in support of atmospheric remote sensing for the Earth (e.g., OCO-2 mission), Mars and Venus. [ABSTRACT FROM AUTHOR]

Pressure-broadened line shape parameters of transitions in the ν 3 band of HDO (ν 0 = 3707.4 cm -1 ) were measured from spectra of HDO and mixtures of HDO and CO 2 for application to accurate retrievals of HDO abundances and D/H ratios for CO 2 -rich planetary atmospheres of Mars and Venus. A few calculated line lists have recently been published on HDO-CO 2 line shapes and their temperature dependences, but the present study represents the first laboratory measurements of those parameters in the ν 3 band; Measurements for nearly 100 transitions in the ν 3 band have been made. Room temperature measurements of self-broadened width and shift coefficients for all of these transitions, line mixing via off-diagonal relaxation matrix element coefficients and quadratic speed dependence parameter were measured for the majority of these transitions. All these measurements were made by simultaneously fitting eleven high-resolution spectra of HDO and HDO-CO 2 mixtures at various temperatures and pressures recorded with the Bruker Fourier transform spectrometer at the Jet Propulsion Laboratory. Two specially built coolable absorption cells with path lengths of 20.38 cm and 20.941 m were used to contain the sample mixtures. Multispectrum nonlinear least squares fitting algorithm was employed in the analysis. Calculations using the Modified Complex Robert-Bonamy formalism (MCRB) were made for the half-width coefficients, their temperature dependences and pressure shift coefficients for the HDO–CO 2 and HDO–HDO collision systems. The calculations were made for all ν 3 band transitions in the 1100–4100 cm -1 region on the HITRAN2012 database. Present measurements are compared with the MCRB calculations and other literature values. [ABSTRACT FROM AUTHOR]

CO 2 -rich planetary atmospheres such as those of Mars and Venus require accurate knowledge of CO 2 broadened HDO half-width coefficients and their temperature dependence exponents for reliable abundance determination. Although a few calculated line lists have recently been published on HDO–CO 2 line shapes and their temperature dependences, laboratory measurements of those parameters are thus far non-existent. In this work, we report the first measurements of CO 2 -broadened half-width and pressure-shift coefficients and their temperature dependences for over 220 transitions in the ν 2 band. First measurements of self-broadened half-width and self-shift coefficients at room temperature are also obtained for majority of these transitions. In addition, the first experimental determination of collisional line mixing has been reported for 11 transition pairs for HDO–CO 2 and HDO–HDO systems. These results were obtained by analyzing ten high-resolution spectra of HDO and HDO–CO 2 mixtures at various sample temperatures and pressures recorded with the Bruker IFS-125HR Fourier transform spectrometer at the Jet Propulsion Laboratory (JPL). Two coolable absorption cells with path lengths of 20.38 cm and 20.941 m were used to record the spectra. The various line parameters were retrieved by fitting all ten spectra simultaneously using a multispectrum nonlinear least squares fitting algorithm. The HDO transitions in the 1100–4100 cm −1 range were extracted from the HITRAN2012 database. For the ν 2 and 2ν 2 -ν 2 bands there were 2245 and 435 transitions, respectively. Modified Complex Robert–Bonamy formalism (MCRB) calculations were made for the half-width coefficients, their temperature dependence and the pressure shift coefficients for the HDO–CO 2 and HDO–HDO collision systems. MCRB calculations are compared with the measured values. [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]

In this study, we report the first experimental measurements of spectral line shape parameters (self- and air-broadened Lorentz half-widths, pressure-shifts, and line mixing (via off-diagonal relaxation matrix elements) coefficients and their temperature dependences, where appropriate) for transitions in the 2ν 3 Q branch manifolds, Q(11)–Q(1) of methane ( 12 CH 4 ), in the 5996.5–6007-cm −1 region. The analysis included 23 high-resolution, high signal-to-noise laboratory absorption spectra recorded with the Bruker IFS-125HR Fourier transform spectrometer (FTS) at JPL. The experimental data were obtained using 12 C-enriched 12 CH 4 and dilute mixtures of 12 CH 4 in dry air in the 130–296 K range using a room-temperature long path absorption cell and, two custom-built coolable cells. In the analysis, an interactive multispectrum fitting software was employed where all the 23 spectra (11 self-broadened and 12 air-broadened) were fit simultaneously. By carefully applying reasonable constraints to the parameters for severely blended lines, we were able to determine a self-consistent set of broadening, shift and line mixing (relaxation matrix coefficients) parameters for CH 4 –CH 4 and CH 4 –air collisions. In the majority of cases, a quadratic speed dependence parameter common for all transitions in each Q( J ) manifold was determined. However, temperature dependences of the Q branch line mixing parameter could not be determined from the present data. Since no other experimental line shape measurements have been reported for this Q-branch, the present results are compared to available values in the HITRAN2012 database. [ABSTRACT FROM AUTHOR]

Pressure-broadened line shapes in the 30013←00001 (ν 1 +4 ν 2 0 +ν 3 ) band of 12 C 16 O 2 at 6228 cm −1 are reanalyzed using new spectra recorded with sample temperatures down to 170 K. High resolution, high signal-to-noise (S/N) laboratory measurements of line shapes (Lorentz air- and self-broadened half-width coefficients, pressure-shift coefficients and off-diagonal relaxation matrix element coefficients) as a function of gas sample temperatures for various pressures and volume mixing ratios are presented. The spectra were recorded using two different Fourier transform spectrometers (FTS): (1) the McMath-Pierce FTS located at the National Solar Observatory on Kitt Peak, Arizona (and reported in Devi et al., J Mol Spectrosc 2007;245:52-80) and, (2) the Bruker IFS-125HR FTS at the Jet Propulsion Laboratory in Pasadena, California. The 19 spectra taken at Kitt Peak were all recorded near room temperature while the 27 Bruker spectra were acquired both at room temperature and colder temperatures (170-296 K). Various spectral resolutions (0.004–0.011 cm −1 ), absorption path lengths (2.46–121 m) and CO 2 samples (natural and 12 C-enriched) were included in the dataset. To maximize the accuracies of the various retrieved line parameters, a multispectrum nonlinear least squares spectrum fitting software program was used to adjust the ro-vibrational constants ( G , B , D etc.) and intensity parameters (including Herman-Wallis terms) instead of directly measuring the individual line positions and intensities. To minimize systematic residuals, line mixing (via off-diagonal relaxation matrix elements) and quadratic speed dependence parameters were included in the analysis. Contributions from other weakly absorbing bands: the 30013←00001 and 30012←00001 bands of 13 C 16 O 2 , the 30013←00001 band of 12 C 16 O 18 O, hot bands 31113←01101 and 32212←02201 of 12 C 16 O 2 , as well as the 40013←10001 and the 40014←10002 bands of 12 C 16 O 2, present within the fitted interval were also measured. Results from previous works and new calculations are compared to present measurements, where appropriate. [ABSTRACT FROM AUTHOR]

In this paper we report line shape parameters of 12 CH 4 for several hundred 2ν 3 transitions in the spectral regions 5891–5996 cm −1 (P branch) and 6015–6115 cm −1 (R branch). Air- and self-broadening coefficients were measured as a function of temperature; line mixing via off-diagonal relaxation matrix element coefficients was also obtained for 47 transition pairs. In total, nearly 1517 positions and intensities were retrieved, but many transitions were too weak for the line shape study. For this analysis, we used 25 high-resolution (0.0056 and 0.0067 cm −1 ) and high signal-to-noise (S/N) spectra of high-purity 12 CH 4 and the same high-purity 12 CH 4 broadened by dry air recorded at different sample temperatures between 130 K and 295 K with the Bruker IFS 125HR Fourier transform spectrometer at JPL. Three different absorption cells were used (1) a White cell set to a path length of 13.09 m for room temperature data, (2) a single-pass 0.2038 m long coolable cell (for self-broadening) and (3) a multipass cell with 20.941 m total path coolable Herriott cell (for air-broadening). In total there were 13 spectra with pure 12 CH 4 (0.27–599 Torr) and 12 air-broadened spectra with total sample pressures of 80–805 Torr and volume mixing ratios (VMR) of methane between 0.18 and 1.0. An interactive multispectrum nonlinear least-squares technique was employed to fit the individual P10–P1 and R0–R10 manifolds in all the spectra simultaneously. Results obtained from the present analysis are compared to other recent measurements. [ABSTRACT FROM AUTHOR]

Accurate knowledge of spectral line shape parameters is important for infrared transmission and radiance calculations in the terrestrial atmosphere. In this paper, we report the self- and air-broadened Lorentz half-widths, pressure-induced shifts and line mixing coefficients (via off-diagonal relaxation matrix elements) along with their temperature dependences for methane ν 2 +ν 3 absorption lines in the 4500–4630 cm −1 region of the Octad. For this, we recorded 14 high-resolution, high signal to noise ratio (S/N) spectra of high-purity (99.95% 12 C-enriched) samples of pure methane and its dilute mixtures in dry air between 298 K and 148 K. A Bruker IFS 125HR Fourier transform spectrometer (FTS) at the Jet Propulsion Laboratory, Pasadena, California, was used to obtain the experimental data. The absorption cell used for this study was a specially built 20.38 cm long coolable cell installed in its sample compartment. The sample pressures for the pure 12 CH 4 spectra were 4.5−385 Torr; for the air-broadened spectra the total pressures ranged between 95 and 300 Torr with the methane volume mixing ratios between 0.04 and 0.097. All 14 spectra were fitted simultaneously using an interactive multispectrum nonlinear least-squares curve fitting technique. The results are compared to values reported in the literature. [ABSTRACT FROM AUTHOR]

The infrared spectrum of 12CH313CH3 is measured between 1345 and 1560 cm-1 using high resolution FT-IR with a 13C-enriched gas sample cooled to 130.3 K. The three fundamentals ν4, ν9 and ν10 (at 1374, 1470 and 1468 cm-1 respectively) and one combination band ν6 + ν11 at 1473 cm-1 are analyzed for the first time. The transitions of ν10 (an infrared inactive "g" mode of the ethane) are observed through its resonant coupling with ν9 (corresponding to a "u" mode of normal ethane). Transitions of ν6 + ν11 are seen due to its strong coupling to ν9. In general, torsional splitting produces two components (as in normal ethane), but in both ν9 and ν10, there is an additional small splitting of these components with degenerate torsional symmetry wherever the interacting ν10 levels become infrared active (from "g ↔ u" mixing); this mechanism is investigated. Several ł-type resonances with Δł = ±2 and Δk = 1 are observed within ν9 and between ν9 and ν10 while the strong interaction between ν9 and ν6 + ν11 plays a role in tuning pairs of levels into resonance. As in normal ethane, a detectable K-doubling occurs in the levels k = ±2, ł = 1 of ν9, and the parallel band ν4 shows an intensity bias, with the R-transitions markedly stronger than the P-transitions, due to its x,y-Coriolis coupling with ν9. The spectrum is analyzed by adopting an appropriate Hamiltonian model, and vibration-rotation-torsion parameters of the four mentioned vibrational states are determined by the least squares process using 1350 observed transition line positions (RMS deviation 3.24 × 10-3 cm-1). The values of rotational and torsional parameters of the vibrational ground state are also improved or determined anew, from data of the present spectrum. Two supplemental files are provided. One shows the fit of line positions, and the other gives the measured positions and intensities at 130 K (with known quantum assignments and lower state energies) so that lines of this molecule can be identified in planetary spectra. [ABSTRACT FROM AUTHOR]

Abstract: The first air broadening line shape parameters were determined for the 2←0 bands of 13C16O near 4166.8cm−1 and 12C18O near 4159.0cm−1. Air-broadened Lorentz half-width coefficients, their temperature dependence exponents; air-induced pressure shift coefficients, their temperature dependences; and air line mixing coefficients were measured. Additionally, speed-dependent line shapes with line mixing employing the off-diagonal relaxation matrix element coefficients were applied to minimize the fit residuals. Finally, individual line positions and line intensities of the two isotopologues were constrained to the well-known theoretical quantum mechanical expressions in order to obtain the rovibrational (G, B, D and H) and band intensity parameters (including Herman–Wallis coefficients). For this, laboratory spectra were recorded at 0.005cm−1 resolution using a temperature-controlled coolable absorption cell configured inside a Bruker IFS 125HR Fourier transform spectrometer. Gas temperatures and pressures for the spectra varied from 150 to 298K and 20 to 700Torr, respectively. Results were obtained from broad-band multispectrum least-squares fitting of the 4000–4360cm−1 spectral region. Four isotope-enriched pure sample spectra and twelve spectra with air+CO samples (13C16O or 12C18O, as appropriate) were fitted simultaneously. The results obtained for 13C16O and 12C18O are compared and discussed. [Copyright &y& Elsevier]

Abstract: Building upon previous studies, we re-investigated the ethane spectrum between 1330 and 1610cm−1 by combining unapodized spectra obtained at room temperature with a Bruker Fourier transform spectrometer (FTS) in Brussels and at 131K with a Bruker FTS in Pasadena. The maximum optical path differences (MOPD) of the two datasets were 450 and 323.7cm, corresponding to spectral resolutions of 0.0020 and 0.0028cm−1, respectively. Of the 15,000 lines observed, over 4592 transitions were assigned to the ν6 (at 1379cm−1), ν8 (at 1472cm−1), ν4+ν12 (at 1481cm−1) and 2ν4+ν9 (at 1388cm−1) bands, and another 1044 transitions were located for the ν4+ν8−ν4 hot band (at 1472cm−1). Our new analysis included an improved implementation of the Hamiltonian calculation needed to interpret the complex spectral structures caused by numerous interactions affecting these four modes of vibration. From these results, we created the first line-by-line database containing the molecular parameters for over 20,000 12C2H6 transitions at 7μm. [Copyright &y& Elsevier]

Abstract: Helium broadening coefficients for the R(10) and the P(2) lines in the ν3 band of 13CO2 have been measured over a large range of temperature (70K–300K). Helium pressure shifts for the R(10) line at several temperatures between 100K and 300K have also been determined. These measurements were obtained with a cold Herriott cell, using the collisional cooling technique to reach the lowest temperatures. They provide an extended dataset for the temperature dependence of widths and shifts. This dataset was compared to theoretical He-broadening coefficients combining quantum scattering calculations and the latest potential energy surface for the system He–CO2 from Korona et al. [T. Korona, R. Moszynski, F. Thibault, J.-M. Maunay, B. Bussery-Honvault, J. Boissoles, P.E.S. Wormer, J. Chem. Phys. 115 (2001) 3074–3084]. [Copyright &y& Elsevier]

The impact of precise spectroscopic measurements on the P(9) multiplet in the ν3 band of 12CH4, obtained using a newly developed cold Herriott cell coupled with a tunable diode laser spectrometer, is examined in the context of remote sensing of methane in the atmosphere. More specifically, the influence of the air-broadening temperature dependence, of line narrowing and of line-mixing effects is assessed when fitting high resolution atmospheric spectra recorded from a balloon in the solar occultation mode. This is achieved by considering residuals and retrieved methane volume mixing ratio profiles. By combining data from previous studies together with new measurements, the expression for the temperature dependence of the broadening coefficient has been revisited. It is shown that a correcting factor applied to the usual law gives better results, when considering all the available measurements from room temperature down to about 10–20 K, as compared to the usual expression of the width versus temperature. These results clearly demonstrate that collision broadening is more sensitive to long-range attractive forces when the temperature is decreased. [ABSTRACT FROM AUTHOR]

Abstract: We measured the temperature dependence of the nitrogen broadening, narrowing and line-mixing coefficients of four lines of the P9 manifold in the ν 3 band of 12CH4 for atmospheric purposes. The data were collected using our tunable diode laser (TDL) spectrometer with active wavenumber control coupled to a newly developed cold Herriott cell with a path length of 5.37m and a temperature uniformity of better than 0.01K along the cell. We recorded and analyzed spectra recorded at sample temperatures between 90K and room temperature. We have investigated the influence of our new results in the inversion model used to retrieve methane profiles from atmospheric spectra; our new results make it possible to retrieve significantly more precise methane profiles. The atmospheric spectra we utilized were obtained by several of us with a balloon-born Fourier Transform infrared experiment in a limb configuration. Differences up to 7% on the retrieved volume mixing ratio were found compared to an inversion model using only HITRAN04 spectroscopic parameters. [Copyright &y& Elsevier]

We present a line profile study at 150, 110 and 80 K for the R(7) line in the fundamental band of 13 CO perturbed by Ar in a new stabilized low-temperature cell cooled by liquid nitrogen. The broadening, shifting and narrowing parameters are determined taking into account the absorber speed dependence by simultaneous least-squares fitting of spectra over a 4-300 Torr pressure range recorded using a frequency-stabilized diode laser spectrometer. When the cell is cooled by liquid helium the (1-0) R(2) line of 13 CO in collision with helium is observed at a temperature of 6.9 K. [ABSTRACT FROM AUTHOR]

The R(0) line profile of the 13CO fundamental band is studied at low concentration in helium from room temperature (296.7 K) to 40 K. A narrowing effect due to molecular confinement (Dicke effect) is observed and analyzed using the Galatry soft collision model. The narrowing parameter is found to be in good agreement with the dynamic friction coefficient deduced from the diffusion coefficient over the entire temperature range. [Copyright &y& Elsevier]

• Obtained H 2 -broadened CH 4 spectra in the v 2 + v 3 band (2.2 µm) at 80 – 370 K. • Fit 28 spectra simultaneously and achieved spectrum fitting residuals better than 1%. • Retrieved H 2 -broadened widths, H 2 -pressue shifts, and their temperature dependences. • Determined collisional line mixing coefficients through full line mixing operation. • Showed J and A/E/F dependence of H 2 -widths for CH4 in the v2+v3 band. We have made the measurements of H 2 -broadened line shape parameters of CH 4 transitions in the v 2 + v 3 band located at 2.2 µm. These measurements support atmospheric opacity calculations of cold giant planets, hot Jupiters, and low mass brown dwarfs, for which H 2 is the dominant atmospheric constituent. For this reason, a series of spectra of pure CH 4 and CH 4 H 2 mixtures were obtained in the Octad (4100–4600 cm−1) region for a wide temperature range between 80 and 370 K using a Bruker 125HR high-resolution Fourier transform spectrometer (FTS) at Jet Propulsion Laboratory (JPL). Three custom-designed gas absorption cells vacuum-coupled to the FTS were used to obtain the spectra. All spectra were fit simultaneously using a multispectrum non-linear least-squares fitting software, which adopts a speed-dependent Voigt line shape using full line mixing taken into account through a relaxation matrix operation. H 2 pressure broadened half-widths, and H 2 pressure-induced shift coefficients were determined in 11 J-manifolds covering P(4) – R(6) plus the Q-branch. The temperature dependences of the width and shift coefficients were determined based upon the power law and the linear models. Collisional line mixing coefficients for CH 4 H 2 were retrieved for ten transition pairs. For the same transitions, speed dependence parameters for the CH 4 H 2 transitions were found to be smaller than for CH 4 -air-broadening. We have compiled the retrieved line parameters in an electronic format and reported as supplemental document. This will facilitate the analyses of planetary and exoplanetary atmospheres using ground-, air- and space-based observations (e.g., Keck I and II, SOFIA, JWST). Image, graphical abstract Figure. Spectrum fitting residuals in the R(6) manifold. (a) with no line mixing, (b) with line mixing, In the bottom panel the observed and calculated spectra where two pairs of transitions mix together, e.g., F 1 and F 2 , and A 1 and A 2 are labeled. The vertical bars (in black at the top of the bottom panel) represent the locations of all transitions included in the calculations. The vertical bars in red, blue, and green indicate the line position of the 1st, 2nd and 3rd sets of five strongest lines each group, respectively. [ Colors available in the online version ]. [ABSTRACT FROM AUTHOR]