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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]

We report experimental measurements of spectral line shape parameters (air-broadened width, shift, and line mixing coefficients) for several transitions in the ν 3 Q branch of methane in the 3000–3023 cm −1 region. 13 high-resolution, room temperature laboratory spectra of pure methane and air-broadened methane recorded with two different Fourier transform spectrometers are fitted. 12 of these spectra were acquired at 0.01 cm −1 resolution with the McMath-Pierce FTS at the National Solar Observatory on Kitt Peak, and one higher-resolution (∼0.0011 cm −1 ) low pressure methane spectrum was obtained with the Bruker IFS-120HR FTS at the Pacific Northwest National Laboratory, in Richland, Washington. All the spectra were obtained using high purity natural samples of CH 4 and lean mixtures of the same natural CH 4 in dry air. For the 12 spectra recorded at Kitt Peak, three different absorption cells (L = 5, 25 and 150 cm) were used while the methane spectrum at PNNL was obtained using a 19.95 cm long absorption cell. For the analysis, an interactive multispectrum nonlinear least squares fitting software was employed where all the 13 spectra were fitted simultaneously. An accurate and self-consistent set of line parameters were determined by constraining a few of those for severely blended transitions. Line mixing was measured for 14 transition pairs for the CH 4 -air collision system. A constant speed dependence parameter, consistent with measured speed dependence values obtained in other methane bands, was applied to all the transitions included in the fitted region. The present measurements are compared to values reported in the literature. [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]

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]

Retrievals of atmospheric composition from near-infrared measurements require measurements of airmass to better than the desired precision of the composition. The oxygen bands are obvious choices to quantify airmass since the mixing ratio of oxygen is fixed over the full range of atmospheric conditions. The OCO-2 mission is currently retrieving carbon dioxide concentration using the oxygen A-band for airmass normalization. The 0.25% accuracy desired for the carbon dioxide concentration has pushed the required state-of-the-art for oxygen spectroscopy. To measure O 2 A-band cross-sections with such accuracy through the full range of atmospheric pressure requires a sophisticated line-shape model (Rautian or Speed-Dependent Voigt) with line mixing (LM) and collision induced absorption (CIA). Models of each of these phenomena exist, however, this work presents an integrated self-consistent model developed to ensure the best accuracy. It is also important to consider multiple sources of spectroscopic data for such a study in order to improve the dynamic range of the model and to minimize effects of instrumentation and associated systematic errors. The techniques of Fourier Transform Spectroscopy (FTS) and Cavity Ring-Down Spectroscopy (CRDS) allow complimentary information for such an analysis. We utilize multispectrum fitting software to generate a comprehensive new database with improved accuracy based on these datasets. The extensive information will be made available as a multi-dimensional cross-section (ABSCO) table and the parameterization will be offered for inclusion in the HITRANonline database. [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]

We investigate the thermal transport originating from the propagation of surface plasmon polaritons (SPPs) in a thin gold stripe. The SPPs are excited by a grating coupler on the Au stripe which was patterned onto a silicon membrane. The transmissivity changes of the Si membrane due to temperature-induced changes of the interference conditions enable measuring the temperature distribution with temporal and spatial resolution better than 1 is and 1 im. With this setup, we demonstrate that SPP excitation, propagation, and decay are accompanied by considerable heating and heat transport. [ABSTRACT FROM AUTHOR]

Accurate knowledge of spectroscopic line parameters of PH3 is important for remote sensing of the outer planets, especially Jupiter and Saturn. In a recent study, line positions and intensities for the Pentad bands of PH3 have been reported from analysis of high-resolution, high signal-to noise room-temperature spectra recorded with two Fourier transform spectrometers (2014) [1]. The results presented in this study were obtained during the analysis of positions and intensities, but here we focus on the measurements of spectral line shapes (e.g. widths, shifts, line mixing) for the 2ν4, ν2 + ν4, ν1 and ν3 bands. A multispectrum nonlinear least squares curve fitting technique employing a non-Voigt line shape to include line mixing and speed dependence of the Lorentz width was employed to fit the spectra simultaneously. The least squares fittings were performed on five room-temperature spectra recorded at various PH3 pressures (~2-50 Torr) with the Bruker IFS-125HR Fourier transform spectrometer (FTS) located at the Pacific Northwest National Laboratory (PNNL), in Richland, Washington. Over 840 Lorentz self-broadened half-width coefficients, 620 self-shift coefficients and 185 speed dependence parameters were measured. Line mixing was detected for transitions in the 2ν4, ν1 and ν3 bands, and their values were quantified for 10 A+A- pairs of transitions via off-diagonal relaxation matrix element formalism. The dependences of the measured half-width coefficients on the J and K rotational quanta of the transitions are discussed. The self-width coefficients for the ν1 and ν3 bands from this study are compared to the self-width coefficients for transitions with the same rotational quanta (J, K) reported for the Dyad (ν2 and ν4) bands. The measurements from present study should be useful for the development of a reliable theoretical modeling of pressure-broadened widths, shifts and line mixing in symmetric top molecules with C3v symmetry in general, and of PH3 in particular. [ABSTRACT FROM AUTHOR]

Abstract: Lorentz self- and air-broadened half width and pressure-induced shift coefficients and their dependences on temperature have been measured from laboratory absorption spectra for nearly 130 transitions in the ν2 band of 12CH4. In addition line mixing coefficients (using the relaxation matrix element formalism) for both self- and air-broadening were experimentally determined for the first time for a small number of transitions in this band. Accurate line positions and absolute line intensities were also determined. These parameters were obtained by analyzing high-resolution (~0.003 to 0.01cm−1) laboratory spectra of high-purity natural CH4 and air-broadened CH4 recorded at temperatures between 226 and 297K using the McMath–Pierce Fourier transform spectrometer (FTS) located at the National Solar Observatory on Kitt Peak, Arizona. A multispectrum nonlinear least squares technique was used to fit short (5–15cm−1) spectral intervals in 24–29 spectra simultaneously. Parameters were determined for ν2 transitions up to J″=16. The variations of the measured broadening and shift parameters with the rotational quantum number index and tetrahedral symmetry species are examined. The present results are also compared with previous measurements available in the literature. [Copyright &y& Elsevier]

We study the excitation and propagation of surface plasmon polaritons (SPPs) on a micron-sized thin gold stripe. Grating couplers are embedded for both excitation of SPPs and detection after propagation. The experimental setup allows measuring of the decay length of the SPPs on the gold stripe excited in the near infrared part of the electromagnetic spectrum. We show that SPPs are transmitted with a surprisingly high probability across a tapered constriction, with smallest lateral dimensions of atomic size. [ABSTRACT FROM AUTHOR]

Abstract: We describe atmospheric validation of and CO2 absorption coefficient databases for use by the Orbiting Carbon Observatory (OCO-2). The OCO-2 mission will collect the measurements needed to estimate column-averaged CO2 dry air mole fraction within 1ppm accuracy without the region- or airmass-dependent biases that would significantly degrade efforts to understand carbon sources and sinks on a global scale. To accomplish this, the forward radiative transfer model used to generate synthetic atmospheric spectra for retrievals must achieve unprecedented spectroscopic fidelity within the short wave infrared CO2 bands sampled by the sensors. The failure of Voigt line shapes and conventional line mixing formulations for such objectives has motivated significant revisions to line shape models used to generate the gas absorption cross sections for the OCO-2 forward model. In this paper, we test line mixing and speed dependent line shapes combined with improved experimental line parameters. We evaluate pre-computed absorption coefficients in the two spectral regions of CO2 absorbtion using high resolution FT-IR laboratory spectra, atmospheric spectra from the Total Carbon Column Observing Network (TCCON), and medium resolution soundings from the space-based Greenhouse Gases Observing Satellite (GOSAT). [Copyright &y& Elsevier]

Abstract: Temperature dependences of pressure-broadened half-width and pressure-induced shift coefficients along with accurate positions and intensities have been determined for transitions in the 2←0 band of 12C16O from analyzing high-resolution and high signal-to-noise spectra recorded with two different Fourier transform spectrometers. A total of 28 spectra, 16 self-broadened and 12 air-broadened, recorded using high-purity (≥99.5% 12C-enriched) CO samples and CO diluted with dry air (research grade) at different temperatures and pressures, were analyzed simultaneously to maximize the accuracy of the retrieved parameters. The sample temperatures ranged from 150 to 298K and the total pressures varied between 5 and 700Torr. A multispectrum nonlinear least squares spectrum fitting technique was used to adjust the rovibrational constants (G, B, D, etc.) and intensity parameters (including Herman–Wallis coefficients), rather than determining individual line positions and intensities. Self- and air-broadened Lorentz half-width coefficients, their temperature dependence exponents, self- and air-pressure-induced shift coefficients, their temperature dependences, self- and air- line mixing coefficients, their temperature dependences and speed dependence have been retrieved from the analysis. Speed-dependent line shapes with line mixing employing off-diagonal relaxation matrix element formalism were needed to minimize the fit residuals. This study presents a precise and complete set of spectral line parameters that consistently reproduce the spectrum of carbon monoxide over terrestrial atmospheric conditions. [Copyright &y& Elsevier]

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: Line positions, Lorentz air-broadened half width and air pressure-induced shift coefficients have been measured for nearly 200 transitions in the ν4 band of 13CH4 from high-resolution spectra recorded with the McMath-Pierce Fourier transform spectrometer. Three room temperature spectra of 13CH4 used in the previous study of Malathy Devi et al. (Air-broadened Lorentz halfwidths and pressure-induced line shifts in the ν4 band of 13CH4. Appl. Opt. 1988; 27: 2296–2308) were analyzed together with a large number of additional spectra of self- and air-broadened CH4 recorded at 210–314K and one room-temperature spectrum of self-broadened 13CH4. Analyses applying the multispectrum nonlinear least squares fitting technique were performed to retrieve the spectral line parameters. In addition to air-broadened half width and shift coefficients, self-broadened half width and shift coefficients were determined for at least 56 13CH4 ν4 transitions. Off-diagonal relaxation matrix element coefficients for air-broadened line mixing were also determined for 28 pairs of P and R transitions in a number of J manifolds, and mixing parameters for self-broadening were also determined for some of these pairs. Temperature-dependences of the pressure-induced shift and mixing parameters for the 13CH4 lines could not be determined from the spectra used in the present analysis, but temperature dependences of the half width coefficients were determined for the strongest transitions. The results of this study are compared with other studies of air- and self-broadened 13CH4 and 12CH4. [Copyright &y& Elsevier]

Abstract: Ethane is a prominent contributor to the spectrum of Titan, particularly in the ν9 region centered near 822cm−1. To improve the spectroscopic line parameters at 12μm, 41 high-resolution (0.0016–0.005cm−1) absorption spectra of C2H6 were obtained at sample temperatures between 211 and 298K with the Bruker IFS 120HR at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington. Two additional spectra were later recorded at ∼150K using a new temperature-stabilized cryogenic cell designed for the sample compartment of the Bruker IFS 125HR at the Jet Propulsion Laboratory (JPL) in Pasadena, California. A multispectrum nonlinear least-squares fitting program was applied simultaneously to all 43 spectra to measure the line positions, intensities, N2- and self-broadened half-width coefficients and their temperature dependences. Reliable pressure-induced shift coefficients could not be obtained, however, because of the high congestion of spectral lines (due to torsional-split components, hot-band transitions as well as blends). Existing theoretical modeling of this very complicated ν9 region permitted effective control of the multispectrum fitting technique; some constraints were applied using predicted intensity ratios, doublet separations, half-width coefficients and their temperature dependence exponents in order to determine reliable parameters for each of the two torsional-split components. For 12C2H6, the resulting retrievals included 17 pQ and rQ sub-bands of ν9 (as well as some pP, rR sub-bands). Positions and intensities were measured for 3771 transitions, and a puzzling difference between previously measured ν9 intensities was clarified. In addition, line positions and intensities were obtained for two 12C2H6 hot bands (ν9+ν4−ν4, ν9+2ν4−2ν4) and the ν9 band of 13C12CH6, as well as several hundred presently unidentified transitions. N2- and self-broadened half-width coefficients were determined for over 1700 transitions, along with 1350 corresponding temperature dependence exponents. Similar to N2- and self-broadened half-width coefficients, their temperature dependence exponents were also found to follow distinctively different patterns. However, while the self- and N2-broaded widths differed by 40%, the temperature dependence exponents of the two broadening gases were similar. The variations of the observed half-width coefficients and their temperature dependences with respect to J, K quantum numbers were modeled with a set of linear equations for each K. The present broadening coefficients compared well with some of the prior measurements. [Copyright &y& Elsevier]

Abstract: The McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory (NSO) on Kitt Peak, Arizona, was used to record infrared high resolution absorption spectra of CO2 spectra broadened by O2. These spectra were analyzed to measure O2-broadened half-width coefficients, O2-induced pressure-shift coefficients and speed dependent parameters for transitions in the 30013←00001 and 30012←00001 bands of 16O12C16O located near 6227 and 6348cm−1, respectively. All spectra were obtained at room temperature using the long path, 6m base path White cell available at NSO. A multispectrum nonlinear least-squares fitting algorithm employing Voigt line shapes modified to include line mixing and speed dependence was used to fit simultaneously a total of 19 spectra in the 6120–6280cm−1 (30013←00001) and 6280–6395cm−1 (30012←00001) spectral regions. 16 of the 19 spectra analyzed in this work were self broadened and three spectra were lean mixtures of CO2 in O2. The volume mixing ratios of CO2 in the three spectra varied between 0.06 and 0.1. Lorentz half-width and pressure-induced shift coefficients were measured for all transitions in the P(50)–R(50) range in both vibrational bands. The results obtained from present analysis have been compared with measurements available in the literature for self-, air-, oxygen- and argon-broadening. No significant differences were observed between the broadening and shift coefficients of the two bands. The N2-broadened half-width and pressure-shift coefficients were computed from measured air- and O2-broadened width and shift coefficients. [ABSTRACT FROM AUTHOR]

Abstract: Accurate values for line positions, absolute line intensities, self-broadened half width and self-pressure-induced shift coefficients have been measured for over 400 allowed and forbidden transitions in the ν4 band of methane (12CH4). Temperature dependences of half width and pressure-induced shift coefficients were also determined for many of these transitions. The spectra used in this study were recorded at temperatures between 210 and 314K using the National Solar Observatory''s 1m Fourier transform spectrometer at the McMath-Pierce solar telescope. The complete data set included 60 high-resolution (0.006–0.01cm−1) absorption spectra of pure methane and methane mixed with dry air. The analysis was performed using a multispectrum nonlinear least squares curve fitting technique where a number of spectra (20 or more) were fit simultaneously in spectral intervals 5–15cm−1 wide. In addition to the line broadening and shift parameters, line mixing coefficients (using the off-diagonal relaxation matrix element formalism) were determined for more than 50 A-, E-, and F-species transition pairs in J manifolds of the P- and R-branches. The measured self-broadened half width and self-shift coefficients, their temperature dependences and the line mixing parameters are compared to self-broadening results available in the literature and to air-broadened parameters determined for these transitions from the same set of spectra. [Copyright &y& Elsevier]

Abstract: Lorentz air-broadened half widths, pressure-induced shifts and their temperature dependences have been measured for over 430 transitions (allowed and forbidden) in the ν 4 band of 12CH4 over the temperature range 210–314K. A multispectrum non linear least squares fitting technique was used to simultaneously fit a large number of high-resolution (0.006–0.01cm−1) absorption spectra of pure methane and mixtures of methane diluted with dry air. Line mixing was detected for pairs of A-, E-, and F-species transitions in the P- and R-branch manifolds and quantified using the off-diagonal relaxation matrix elements formalism. The measured parameters are compared to air- and N2-broadened values reported in the literature for the ν 4 and other bands. The dependence of the various spectral line parameters upon the tetrahedral symmetry species and rotational quantum numbers of the transitions is discussed. All data used in the present work were recorded using the McMath–Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak. [Copyright &y& Elsevier]

We report the first extensive experimental measurements of Ar-broadened half-width and pressure-induced shift coefficients, speed dependence parameters, and line mixing coefficients for the 30013←00001 and 30012←00001 bands of 16O12C16O centered near 6227 and 6348 cm–1, respectively. These parameters were determined from 15 self-broadened and six Ar-broadened CO2 spectra recorded at room temperature with long absorption path lengths (25 to 121 m) using the McMath–Pierce Fourier transform spectrometer (FTS) at the National Solar Observatory. All 21 spectra were fit simultaneously using a multispectrum nonlinear least-squares technique. The line positions and line intensities were constrained to quantum mechanical expressions to obtain maximum accuracies in the retrieved parameters. Speed-dependent line shapes with line mixing (via the relaxation matrix formalism) were required to remove systematic errors in the fit residuals using only the Voigt profile. Remaining fit residuals were minimized by adjusting the half-width and pressure-induced shift coefficients of the overlapping 31113←01101 and 31112←01101 hot bands. We compare the Ar-broadening parameters with those recently determined for self- and air-broadening in the 30012←00001 and 30013←00001 bands and also with other Ar-broadening values from the literature, as appropriate. [ABSTRACT FROM AUTHOR]

Abstract: Line position, intensity and line shape parameters (Lorentz widths, pressure shifts, line mixing, speed dependence) are reported for transitions of the 30013←00001 band of 16O12C16O (ν 0 =6227.9cm−1). The results are determined from 26 high-resolution, high signal-to-noise ratio spectra recorded at room temperature with the McMath-Pierce Fourier transform spectrometer. To minimize the systematic errors of the retrieved parameters, we constrained the multispectrum nonlinear least squares retrieval technique to use quantum mechanical expressions for the rovibrational energies and intensities rather than retrieving the individual positions and intensities line by line. Self- and air-broadened Lorentz width and pressure-induced shift, speed dependence and line mixing (off-diagonal relaxation matrix elements) coefficients were adjusted individually. Errors were further reduced by simultaneously fitting the interfering absorptions from the weak 30012←00001 band of 16O13C16O as well as the weak hot bands 31113←01101, 32213←02201, 40014←10002 and 40013←10001 of 16O12C16O in this spectral window. This study complements our previous work on line mixing and speed dependence in the 30012←00001 band (ν 0 =6347.8cm−1) [V.M. Devi, D.C. Benner, L.R. Brown, C.E. Miller, R.A. Toth, J. Mol. Spectrosc. 242 (2007) 90-117] and provides key data needed to improve atmospheric remote sensing of CO2. [Copyright &y& Elsevier]

Abstract: Two general techniques significantly improve both the accuracy and speed of spectral line shapes that use only the complex Voigt function. Such line shape functions include the Voigt line profile, which is closely related to the real part of this function. The first technique is a new algorithm, which trades a small amount of RAM (at most 1.49 megabytes) for a considerable gain in speed and accuracy. The accuracy is one part in 106 of the function itself. In addition, the derivatives of the function with respect to x and y are returned with an accuracy of 0.5%. The algorithm is up to nine times faster than the Drayson or Humlíček algorithms and about two orders of magnitude more accurate. A second independent improvement is a set of simple criteria to decide when an evaluation is required and when a value of zero can be assumed. This section alone can reduce the computation time by three orders of magnitude or more and it can be applied to algorithms using any Voigt approximation. [Copyright &y& Elsevier]

Abstract: Intensity and line shape parameters which predict spectral lines with absolute accuracies better than 0.3% have been determined for transitions of the 30012←00001 band of 16O12C16O centered near 6348cm−1 from 26 high resolution, high signal-to-noise ratio spectra recorded at room temperature with the McMath–Pierce Fourier transform spectrometer. To maximize the accuracies of the retrieved parameters, the multispectrum non-linear least squares retrieval technique was modified to adjust the rovibrational constants (G, B, D, etc.) and intensity parameters, including Herman–Wallis terms, rather than retrieving the individual positions and intensities. Speed-dependent Voigt line shapes with line mixing were required to remove systematic errors in the fit residuals. Self- and air-broadening (widths and pressure-induced shifts, speed dependence parameters) and line mixing (off-diagonal relaxation matrix elements) coefficients were thus obtained in the multispectrum fit. Remaining errors were minimized by fitting the weak 30011←00001 band of 16O13C16O as well as the weak hot bands 31112←01101, 32212←02201, 40012←10001, and 40013←10002 of 16O12C16O that contribute interfering absorptions in this spectral window. This study presents the most extensive set of measurements to date for self- and air-broadening and self- and air-shift coefficients of a near infrared band of CO2. This is also the first study where line mixing parameters have been experimentally determined for any parallel CO2 band. [Copyright &y& Elsevier]

Abstract: Line mixing has been measured for two pairs of transitions in the ν2 band of H2 16O. The rotational assignments of the four lines (in terms of the rotational quantum numbers J, K a and K c) are (a) two P branch lines: (1 0 1)←(2 1 2) mixing with (2 1 2)←(3 0 3) at 1539.061 and 1540.300cm−1, respectively; and (b) two R branch lines: (3 0 3)←(2 1 2) mixing with (2 1 2) ←(1 0 1) at 1652.400 and 1653.267cm−1, respectively. Pressure broadening coefficients of H2O (halfwidths, pressure shifts and off-diagonal relaxation matrix elements) are reported for seven broadeners (self, H2, He, CO2, N2, O2 and air) from retrievals performed by multispectrum fitting implemented with line mixing. The effect is largest for self- and H2-broadening. [Copyright &y& Elsevier]

Abstract: Absolute intensities, self- and air-broadening coefficients, self- and air-induced shift coefficients and their temperature dependences have been determined for lines belonging to the P- and R-branches of the ν2 band of H12C14N centered near 712cm−1. Infrared spectra of HCN in the 14-μm region were obtained at high resolution (0.002–0.008cm−1) using two different Fourier transform spectrometers (FTS), the McMath-Pierce FTS at the National Solar Observatory on Kitt Peak and the Bruker IFS 120HR FTS at the Pacific Northwest National Laboratory. Spectra were recorded with 99.8% pure HCN as well as lean mixtures of HCN in air at various temperatures ranging between +26 and −60°C. A multispectrum nonlinear least squares technique was used to fit selected intervals of 36 spectra simultaneously to obtain the line positions, intensities, broadening, and shift parameters. The measured line intensities were analyzed to determine the vibrational band intensity and the Herman–Wallis coefficients. The measured self-broadening coefficients vary between 0.2 and 1.2cm−1atm−1 at 296K, and the air-broadening coefficients range from 0.08 to 0.14cm−1atm−1 at 296K. The temperature dependence exponents of self-broadening range from 1.46 to −0.12 while the corresponding exponents for air broadening vary between 0.58 and 0.86. The present measurements are the first known determination of negative values for the temperature dependence exponents of HCN-broadening coefficients. We were able to support our self-broadening measurements with appropriate theoretical calculations. Our present measurements are compared, where possible, with previous measurements for this and other HCN bands, as well as the parameters that are included in the 2000 and 2004 editions of the high-resolution transmission (HITRAN) database. [Copyright &y& Elsevier]

Abstract: Air-broadened linewidths, pressure-induced shift coefficients and their temperature dependences were retrieved for over 1000 transitions in the ν3 band of 14N16O2 at 6μm. In addition, precise line center positions and relative intensities were also determined. The results were obtained by fitting simultaneously 27 spectra recorded at high resolution (0.002–0.006cm−1) with two Fourier transform spectrometers and gas sample temperatures ranging from 206 to 298K. It was necessary to modify the multispectrum fitting software to accommodate constraints on the retrieved parameters of closely spaced spin–split doublets in order to successfully determine their broadening and shift parameters. The variations of the widths, shifts and their temperature dependences with the quantum numbers were investigated. Subsets of the observed linewidths were reproduced to within 3% using an empirical smoothing function. [Copyright &y& Elsevier]

High-resolution (0.005 cm-1) infrared absorption spectra of HCN in the 2ν2 band region near 1411 cm-1 have been recorded at room temperature using the Bruker IFS120HR Fourier transform spectrometer located at Pacific Northwest National Laboratory. Four spectra of high-purity (99.8%) HCN together with three spectra of lean mixtures (∼3%) of HCN in dry air were simultaneously fit using a multispectrum nonlinear least-squares procedure. The analysis yielded room temperature values for absolute intensities, self- and air-broadening coefficients, and self- and air-induced pressure shift coefficients for numerous lines in the 2ν20 band of H12C14N. In addition, intensities, self- and air-broadening coefficients for several lines of the 3ν21-ν21 hot band, as well as intensities for a number of lines in the 2ν20 band of H13C14N, were also determined. Since there are no previous measurements of broadening and shift parameters reported in the 2ν20 band, our results are compared with values recently determined in the ν1 band of H12C14N and with current HITRAN values. [Copyright &y& Elsevier]

The infrared spectrum of HCN in the region between 3150 and 3450 cm−1 has been recorded at 0.005 and 0.008 cm−1 resolution using two different Fourier transform spectrometers, the McMath–Pierce Fourier transform spectrometer located at the National Solar Observatory (on Kitt Peak) and the Bruker-120HR Fourier transform spectrometer situated at the Pacific Northwest National Laboratory at Richland, Washington. Room temperature measurements were made of positions, absolute intensities, self-broadening and self-shift coefficients for individual lines belonging to the HCN ν1 band centered near 3311 cm−1. These are to our knowledge the first extensive set of self-broadening and self shift measurements in the band. In addition, intensities, self-broadening and self-shift coefficients for several lines of the ν1+ν21−ν21 hot band and several intensities for lines in the H13C14N and H12C15N isotopomers were also determined. A multispectrum nonlinear least-squares fitting algorithm was used to fit the entire spectral region covering the 3200–3400 cm−1 region of up to 27 spectra simultaneously. The measured line intensities in the ν1 band were further analyzed to derive the vibrational band intensity and the Herman–Wallis coefficients. Differences in line intensities between 5 and 10% are found with respect to present measurements and the values given in the HITRAN database for m values beyond 25 in the P branch and 5 in the R branch. [Copyright &y& Elsevier]

Two editions of the methane line parameters (line positions, intensities and broadening coefficients) available from HITRAN in 2000 and 2001 are described. In both versions, the spectral interval covered was the same (from 0.01 to 6184.5 cm−1), but the database increased from 48,033 transitions in 2000 to 211,465 lines in 2001 because weaker transitions of 12CH4 and new bands of 13CH4 and CH3D were included. The newer list became available in 2001 in the “Update” section of HITRAN. The sources of information are described, and the prospects for future improvements are discussed. [Copyright &y& Elsevier]

Extensive high-resolution experimental determination is provided for air- and N2-broadening and pressure shift coefficients for the two 13C16O2 laser bands (located at 913.4 and 1017.6 cm−1, respectively), in addition to new measurements of self-broadening and self-shift coefficients for the 12C16O2 laser bands. These parameters were determined from analysis of spectra recorded with the McMath–Pierce Fourier transform spectrometer (FTS) of the National Solar Observatory on Kitt Peak, Arizona. We used a multispectrum nonlinear least-squares fitting technique to analyze 30 long path, room temperature absorption spectra. By combining the spectra of 12CO2 and 13CO2 in the same fit we were able to obtain a consistent set of line parameters for both molecules. The results obtained for the 12CO2 and 13CO2 laser bands were compared with each other, with values in the HITRAN database, and with values reported in the literature for CO2 bands. Comparisons revealed no significant differences in the broadening or shift coefficients between the two laser bands. The coefficients determined for the two isotopomers agreed closely. [Copyright &y& Elsevier]

Line intensities of the two 12C16O2 laser bands (ν3–ν1 and ν3–2ν20) centered near 960.9 and 1063.7 cm−1, respectively, were obtained from analysis of 30 room temperature long path laboratory absorption spectra recorded at 0.0028 and 0.0053 cm−1 resolution with the McMath–Pierce Fourier transform spectrometer at the National Solar Observatory (located on Kitt Peak). The spectra were analyzed simultaneously with the multispectrum nonlinear least-squares fitting procedure. The measured line intensities were further analyzed to derive the vibrational band intensities and Herman–Wallis coefficients. [Copyright &y& Elsevier]

In this study we report the first high-resolution measurements of pressure broadening and pressure-induced shift coefficients due to nitrogen for rovibrational transitions in the ν3 band of 13C16O2. N2 broadening and shift coefficients of ν312C16O2 transitions were also measured. In addition, nitrogen-broadening coefficients for many transitions in the ν3+ν2−ν2 hot band of 13C16O2 as well as the ν3 band of 13C16O18O were also determined. The results were obtained by analyzing five high-resolution (0.0028 cm−1) room temperature laboratory absorption spectra with a multispectrum nonlinear least-squares spectral fitting technique. The data were recorded with the McMath-Pierce Fourier transform spectrometer of the National Solar Observatory on Kitt Peak using a 4.08 cm sample cell, total pressures up to 470 Torr, and a 90% 13C-enriched CO2 sample. For the pressure-broadened spectra the 13C16O2 volume-mixing ratios were⩽0.5%. Similar to broadening coefficients, the measured pressure shift coefficients were also found to be transition dependent. However, the shift coefficients were different in the P and R branch lines with the same rotational quantum number, J. The measured nitrogen-broadening coefficients range from 0.0960 to 0.0643 cm−1 atm−1 at 296 K. The measured shift coefficients were all negative and varied between 0 and −0.0036 cm−1 atm−1. The results obtained are compared with other values reported in the literature. [Copyright &y& Elsevier]

Self- and hydrogen-broadening coefficients and pressure-shift coefficients for the first overtone band transitions of 12C16O at room temperature have been determined through analysis of nine high-resolution (0.0055 cm−1) absorption spectra. These spectra were recorded using the 1-m Fourier transform spectrometer (FTS) at the McMath-Pierce facility of the National Solar Observatory on Kitt Peak, Arizona. Because of the short path length of the sample cell (10.0 cm), the volume mixing ratios of CO in hydrogen were relatively high, ∼18–22%, to achieve measurable absorption. These large volume-mixing ratios necessitated the simultaneous determination of the CO self-broadening and self-shift coefficients along with the hydrogen-broadening and hydrogen-induced shift coefficients. We have determined these coefficients at room temperature, along with line positions and absolute intensities, for the P(27) through R(27) 12C16O 2-0 transitions by fitting the entire spectral interval from 4130 to 4345 cm−1 in all nine spectra simultaneously using our multispectrum nonlinear least-squares procedure. Our intensity measurements are consistently low (1–6%) compared with the HITRAN values but the majority of the intensities are within 4% of the HITRAN values. The values of self-broadening coefficients vary from 0.0452 to 0.0862 cm−1 atm−1 at 296 K and those of hydrogen-broadening coefficient range between 0.0475 and 0.0795 cm−1 atm−1 at 296 K. All of our measured self- and hydrogen-shift coefficients are negative and range from −0.002 to −0.008 cm−1 atm−1. With the pressure and path length used in our study we did not find evidence of significant line mixing in either the self- or hydrogen-broadened spectra. This study represents the first high-resolution experimental determination of hydrogen-induced pressure broadening and pressure-shift coefficients in the 2-0 band of 12C16O at room temperature. [Copyright &y& Elsevier]

We report the first measured Lorentz self- and nitrogen-broadening and the corresponding pressure-shift coefficients in the ν5(E) perpendicular band of 12CH3D between 1275 and 1600 cm−1. The multispectrum fitting technique allowed us to analyze simultaneously both self-broadened and N2-broadened spectra recorded at 0.005 to 0.006-cm−1 resolution with a Fourier transform spectrometer located at Kitt Peak. Self-broadening coefficients for over 550 transitions and self-shift coefficients for more than 480 transitions with rotational quantum numbers up to J″=17 and K″=14 were determined. Nitrogen-broadening and nitrogen pressure-induced shift coefficients were determined for more than 300 of those transitions. The measured broadening coefficients vary from 0.020 to about 0.091 cm−1 atm−1 at 296 K. The measured pressure-shift coefficients had values extending from about −0.014 to +0.005 cm−1 atm−1. Very few of the pressure-shift coefficients were positive, and the positive pressure-shift coefficients were mostly associated with the J″=K″ transitions in the PQ sub-bands. The J″=K″ transitions in the PP and RR sub-bands were associated with the smallest broadening coefficients. Our measurements also included 46 forbidden lines with ΔK=±2 (10 OP, 9 OQ,3 QP, 7 QQ, 1 QR, 13 SQ and 3 SR). The off-diagonal relaxation matrix element coefficients, Wij, in cm−1 atm−1 at 296 K which are associated with line mixing were determined for a few transitions with K″=3 (A+A−splitting) in the PP, PQ and RP sub-bands. We have examined the dependence of the measured parameters on J,K quantum numbers and also developed empirical expressions to describe the broadening coefficients in terms of J and K. [Copyright &y& Elsevier]

Lorentz self- and nitrogen-broadening coefficients as well as self- and nitrogen-pressure induced shift coefficients were measured at room temperature for more than 440 transitions in the QP, QQ and QR branches of the ν3(A1) parallel band of 12CH3D. The simultaneous multispectrum nonlinear least-squares fitting analysis was performed in the 1140–1440 cm−1 region using 14 spectra of room temperature gas recorded with the McMath–Pierce Fourier transform spectrometer (0.005 cm−1 unapodized resolution) of the National Solar Observatory (NSO) on Kitt Peak. The measured self-broadening coefficients varied from about 0.025 cm−1 atm−1 at 296 K for high J, K transitions to about 0.09 cm−1 atm−1 at 296 K for low J, K transitions. In the case of nitrogen broadening these values ranged from about 0.023 to 0.073 cm−1 atm−1 at 296 K. The majority (>90%) of the self-pressure induced shift coefficients as well as nitrogen-pressure-induced shift coefficients was negative with values varying between approximately 0 and −0.012 cm−1 atm−1. However, similar to air-induced pressure-shift coefficients determined in an earlier study, the measured self- and nitrogen-induced pressure-shift coefficients were positive for the QR-branch transitions with J″=K″, varying from 0 to about +0.009 cm−1 atm−1. Weak line mixing effects were observed in several high-J lines with K″=3 splitting and approximate values for the off-diagonal relaxation matrix-element coefficients were determined for a few A1A2 (A+A−) split components. Comparisons are made between the measured self- and nitrogen-broadening and shift coefficients, and the results are also compared with measurements in other bands. [Copyright &y& Elsevier]

Abstract: We review efforts to experimentally determine absolute line intensities for ozone transitions in the 9–11μm spectral region over the last several decades. Much of this work has been driven by the requirements for remote sensing of terrestrial atmospheric ozone. While significant progress has been achieved, discrepancies persist among various infrared measurements, and the relation between infrared and ultraviolet standards is not clearly resolved. [Copyright &y& Elsevier]

Abstract: Line positions, intensities, Lorentz self- and N2-broadened half-width coefficients have been measured for PQ3, PQ2, PQ1, RQ0, RQ1, RQ2, and RQ3 sub-band transitions in the ν 9 fundamental band of 12C2H6. A multispectrum nonlinear least-squares fitting technique was used to fit up to 17 high-resolution (∼0.00156cm−1), room temperature absorption spectra of pure (99.99% chemical purity) natural sample of ethane and lean mixtures of the high-purity ethane diluted with N2. A Bruker IFS 120HR Fourier transform spectrometer located at the Pacific Northwest National Laboratory (PNNL), in Richland, Washington was used to record the data. A standard Voigt line shape was assumed to fit all the data since no line mixing or other non Voigt line shapes were required to fit any of the spectra used in the analysis. Short spectral intervals (∼2–2.5cm−1) of all 17 spectra covering a specific PQ or RQ sub-band were fit simultaneously. For the first time in an ethane band, pressure-broadened half-width coefficients were determined for the torsional-split components. However, for better reliability of the retrieved coefficients for the weaker components (transitions with large intensity ratios of 4:1 or 3:1 for most K levels between the strong and weak components), constraints were used such that the half-width coefficients of both torsional-split components for a given J were identical for a specific broadening gas. No pressure-induced shift coefficients were necessary to fit the spectra to their noise level. The present study revealed for the first time the dependence of self- and N2-broadened half-width coefficients upon the J, K quantum numbers of the transitions in ethane. A number of transitions belonging to the ν 9+ν 4−ν 4 and the ν 9+2ν 4−2ν 4 hot bands were also observed in the fitted regions and measurements were made when possible. [Copyright &y& Elsevier]

In this study, 39 high-resolution spectra of pure and air-broadened CO2 recorded at temperatures between 215 and 294 K were analyzed using a multispectrum nonlinear least-squares technique to determine temperature dependences of air-broadened Lorentz half-width and air-induced pressure shift coefficients for over 100 individual 12C16O2 transitions in the 30012←00001 (at 6348 cm–1) and 30013←00001 (at 6228 cm–1) bands. Data were recorded with two different Fourier transform spectrometers (Kitt Peak FTS at the National Solar Observatory in Arizona and the Bomem FTS at NRC, Ottawa), with absorption path lengths ranging between 25 and 121 m. The sample pressures varied between 11 torr (pure CO2) and 924 torr (CO2-air) with volume mixing ratios of CO2 in air between ~1.5% and 11% (1 torr = 133.322 4 Pa). To minimize systematic errors and increase the accuracy of the retrieved parameters, a constrained multispectrum nonlinear least-squares fitting technique was used to include theoretical quantum mechanical expressions for the rovibrational energies and intensity parameters rather than retrieving the individual positions and intensities line by line. The results suggest no detectable vibrational dependence for the temperature dependences for the air-broadened Lorentz half-width coefficients and the air-induced pressure shift coefficients. The half-width coefficients and temperature dependence exponents were modeled using semiclassical calculations based upon the Robert–Bonamy formalism. A good agreement is seen between the measurements and theoretical calculations. Beyond |m| = 26, a simple scaling factor (0.96) has been applied to the calculated half-width coefficients to match the experimental measurements. [ABSTRACT FROM AUTHOR]

The dewetting process, which appears upon laser-induced melting of flat nanostructures and leads to a jumping of the droplets off the surface, is used for deposition of nano-particles onto a second substrate. Limitations in materials and particle sizes are discussed and experimentally verified. The experiments show that a variety of metals can be deposited in a size ranging from tens up to several hundreds of nanometers. [ABSTRACT FROM AUTHOR]