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SCISAT-1, also known as the Atmospheric Chemistry Experiment, is a satellite mission for remote sensing of the Earth's atmosphere, launched on 12 August 2003. The primary instrument on the satellite is a 0.02 [cm.sup.-1] resolution Fourier-transform spectrometer operating in the mid-IR (750-4400 [cm.sup.-1]). We describe the approach developed for the retrieval of atmospheric temperature and pressure from the troposphere to the lower thermosphere as well as the strategy for the retrievals of volume-mixing ratio profiles of atmospheric species. OCIS codes: 010.1280, 280.0280, 300.6340.

New high-resolution infrared and UV/visible spectra of 107AgH, 109AgH, 107AgD, and 109AgD have been recorded with a Fourier transform spectrometer. The new line positions are combined with published microwave and older electronic A 1Σ+-X 1Σ+ data and used, first in a decoupled analysis of the X state alone, and then in a global multi-isotopologue analysis which yields comprehensive descriptions of both the X 1Σ+ and A 1Σ+ states of all four isotopologues of AgH. While the A state was long believed to be heavily perturbed, it is shown that its irregular spectrum merely reflects an unusual potential function shape. A direct fit of all data to appropriate radial Hamiltonians yields analytic potential-energy functions and Born-Oppenheimer breakdown radial functions for the ground X 1Σ+ and A 1Σ+ states. [ABSTRACT FROM AUTHOR]

Fourier transform emission spectra of D[sub 2]O vapor were recorded at a temperature of 1500 °C in the wavenumber range 380–1880 cm[sup -1]. 15 346 lines were measured, of which the majority were identified as belonging to D[sub 2]O. The spectrum was analyzed using variational nuclear motion calculations based on spectroscopically determined potential-energy surfaces. Initial assignments were made using a potential surface obtained by fitting a high accuracy ab initio potential. The new assignments were used to refine the potential surface, resulting in additional assignments. A total of 6400 D[sub 2]O transitions were assigned and 2144 new D[sub 2]O energy levels were obtained. Transitions involving the 4ν[sub 2] and 5ν[sub 2] bending states, with band origins of 4589.30 (±0.02) and 5679.6 (±0.1) cm[sup -1], respectively, were assigned for the first time.© 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

• High resolution Fourier transform spectroscopy of propene at 202–295 K. • Infrared absorption cross sections of propene broadened by N 2 for 450–1250 cm−1 region. • Infrared absorption cross sections of propene broadened by H 2 for 2680–3220 cm−1 region. • Data are useful for planetary atmospheres including giant planets and Titan. Propene (C 3 H 6) has been measured in the planetary atmospheres of Earth and Titan, and may be detected in the giant planets by infrared spectroscopy. Propene infrared absorption cross sections have been determined in the 2680–3220 cm−1 and 450–1250 cm−1 regions by high-resolution Fourier transform spectroscopy with H 2 and N 2 , respectively, as broadening gases. Samples of propene were held at 202, 232, 265, 297 K. [ABSTRACT FROM AUTHOR]

• Atmospheric chemistry Experiment, ACE. • Characteristic IR solar absorption spectroscopy of clouds and aerosol particles. • Cloud and aerosol particle spectral analysis and modeling. • Satellite remote sensing by Fourier transform infrared spectroscopy. Clouds and aerosols play a vital role in the Earth's climate. Detecting polar mesospheric clouds, polar stratospheric clouds and aerosols is useful for monitoring climate change and atmospheric chemistry. ACE (Atmospheric Chemistry Experiment) satellite data are used to provide an infrared spectral atlas of polar mesospheric clouds, three types of polar stratospheric clouds (nitric acid trihydrate, sulfuric/nitric acid ternary solutions, and ice), cirrus clouds, stratospheric smoke from fires and sulfate aerosols. Most of the example spectra have been modeled using the appropriate optical constants and the calculated extinction of sunlight by the particles. [ABSTRACT FROM AUTHOR]

• High resolution infrared Fourier transform spectroscopy. • Absorption cross sections of n-butane, n-pentane, cyclopentane and cyclohexane. • For remote sensing in planetary atmospheres. The infrared absorption cross sections of pure n -butane, n -pentane, cyclopentane and cyclohexane have been measured in the 3.3 µm region (and 6.8 µm region for cyclopentane) by high resolution Fourier transform spectroscopy. The samples had temperatures of 294 K and 230 K for n -butane, 294 K and 218 K for n -pentane, 296 K and 235 K for cyclopentane, and 294 K and 222 K for cyclohexane. These spectra are important for molecular identification in extraterrestrial environments such as Saturn's moon Titan, giant planets and exoplanets. All spectra are provided as data point files. [ABSTRACT FROM AUTHOR]

Abstract: ACE is a Canadian-led satellite mission that is measuring the concentrations of more than 30atmospheric constituents by absorption spectroscopy using the Sun as a light source. The principal goal of the ACE mission is to make measurements that will improve understanding of the chemical and dynamic processes that control the distribution of ozone in the upper troposphere and stratosphere. The ACE instruments are an infrared Fourier transform spectrometer (FTS), a UV/visible/near IR spectrograph and a two-channel solar imager, all working in solar occultation mode. The high-resolution (0.02cm−1) FTS is the primary instrument on the satellite, and it covers the mid-infrared spectral region (750–4400cm−1). [Copyright &y& Elsevier]

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• High resolution Fourier transform spectroscopy of propene at 202–295 K. • Infrared absorption cross sections of propene for 2680–3220 cm−1 region. • Helium and nitrogen used as broadening gases. • Data are useful for planetary atmospheres including giant planets and Titan. Propene infrared absorption cross-sections are important for quantitative analysis of atmospheric spectra. Propene has been observed in Titan's atmosphere and may be detected in the atmospheres of giant planets. Infrared absorption cross-sections of propene (C 3 H 6) have been measured in the 2680–3220 cm−1 region by high-resolution Fourier transform spectroscopy. Samples of propene were held at 202, 232, 265, 295 K with helium and nitrogen broadening gas pressures of 10, 30, 100 Torr. The cross section files are available for download. [ABSTRACT FROM AUTHOR]

• High-temperature methane in planetary atmospheres. • Pressure broadening and shifts of methane lines in the V 3 band. • Temperature dependence of broadening and shift coefficients. Methane (CH 4) spectra in the ν 3 band near 3.3 m were measured for 0, 50, 150, 240, 320, and 400 Torr pressure of added hydrogen. The spectra were recorded using a high resolution Fourier transform spectrometer. The CH 4 spectra were measured at 5 different temperatures from room temperature up to ∼ 1100 K. A multi-spectrum non-linear least squares fit method was used to determine the line parameters at each temperature. Voigt lineshape functions were used to determine the broadening and shifting of methane lines in the P and R branches. The temperature dependence of exponent parameters for the line width and the linear frequency shift coefficients were determined from a fit for temperatures ranging from 296 to 1098 K. The temperature dependence of the retrieved line broadening parameters was observed to follow the Double Power Law (DPL) proposed by Gamache and Vispoel. The temperature dependence of the pressure shift coefficients follows a linear trend for the first three temperatures. The pressure broadening parameters decrease with increasing temperature, and the pressure shift parameters increase with increasing temperature, especially for the first three temperatures. Finally, the dependence of pressure broadening (γ 0) and shift (δ 0) parameters on the rotational quantum number (J) was studied. The pressure broadening coefficients decrease about 20–30% for temperatures up to 894 K and about 40% for 1098 K, with increasing J quantum number. A complete set of fitted parameters including line position (σ), line intensity (S), pressure broadening (γ 0), shifting (δ 0), and their corresponding fitting errors are provided in supplementary tables. [ABSTRACT FROM AUTHOR]

• High resolution absorption spectra of ethane, C 2 H 6 , in the 3.3 µm region (2550–3350 cm − 1). • Absorption cross sections for ethane broadened by H 2 or He. • Measurements performed for 203–295 K. • Useful for analysis of spectra of giant planets. The infrared absorption cross sections of ethane (C 2 H 6) have been measured in the 3.3 µm region by high resolution Fourier transform spectroscopy. The ethane samples had temperatures of 203, 233, 263, 295 K with broadening gas pressures of 10 Torr, 30 Torr and 100 Torr of hydrogen or helium. These cross sections are useful for the interpretation of spectra of the giant planets. [ABSTRACT FROM AUTHOR]

High resolution infrared absorption cross sections of isobutane, (CH 3) 3 CH, were measured in the 1050–1900 cm−1 spectral range by Fourier transform spectroscopy. Four sample temperatures (210, 234, 265 and 296 K) were used with three pressures (10, 30 and 100 Torr) of N 2 and H 2 broadening gas. Spectra of pure isobutane samples were also recorded. These cross sections are useful for the interpretation of infrared spectra of the Giant Planets and Titan. The isobutane cross sections give an upper limit of 3.91e-8 for its fractional abundance on Titan based on CIRS/Cassini infrared spectra. Using n -butane, CH 3 (CH 2) 2 CH 3 , cross sections from the literature, we obtain an upper limit of 5.13e-7 for its abundance on Titan. The combined upper limit for both isomers of butane, C 4 H 10 , on Titan of 5.52e-7 is consistent with the lower limit of recent model predictions. [ABSTRACT FROM AUTHOR]

The spectrum of CrH has been reinvestigated in the 9000–15 000 cm[sup -1] region using the Fourier transform spectrometer of the National Solar Observatory. The 1-0 and 1-1 bands of the A [sup 6]Σ[sup +]-X [sup 6]Σ[sup +] transition have been measured and improved spectroscopic constants have been determined. A value for the 2-0 band origin has been obtained from the band head using estimated spectroscopic constants. These data provide a set of much improved equilibrium vibrational and rotational constants for the A [sup 6]Σ[sup +] state. An accurate description of the A-X transition has been obtained using a multireference configuration interaction approach. The inclusion of both scalar relativity and Cr 3s3p correlation are required to obtain a good description of both states. The ab initio computed Einstein coefficients and radiative lifetimes are reported. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

• Global isotopologue fractionations of ozone measured by the ACE satellite mission. • A high-resolution Fourier transform spectrometer is used in solar occultation method. • Heavy isotopologues are enriched in tropical stratosphere and in the upper stratosphere of the Antarctic polar vortex. Near global ozone isotopologue distributions have been determined from infrared solar occultation measurements of the Atmospheric Chemistry Experiment (ACE) satellite mission. ACE measurements are made with a high resolution Fourier transform spectrometer. Annual and seasonal latitudinal fractionation (δ value) distributions of the ozone isotopologues 16O16O18O, 16O18O16O and 16O17O16O were obtained. Asymmetric ozone (16O16O18O) shows higher fractionation compared to symmetric ozone (16O18O16O). The maximum ozone fractionation occurs in the tropical stratosphere as expected from the contribution of photolysis to the enrichment of heavy isotopologues. An enhancement of the heavy ozone isotopologues is also seen in the upper stratosphere of the Antarctic polar vortex. [ABSTRACT FROM AUTHOR]

Carbon tetrachloride (CCl 4 ) is one of the species regulated by the Montreal Protocol on account of its ability to deplete stratospheric ozone. As such, the inconsistency between observations of its abundance and estimated sources and sinks is an important problem requiring urgent attention (Carpenter et al., 2014) [5] . Satellite remote-sensing has a role to play, particularly limb sounders which can provide vertical profiles into the stratosphere and therefore validate stratospheric loss rates in atmospheric models. This work is in two parts. The first describes new and improved high-resolution infra-red absorption cross sections of carbon tetrachloride/dry synthetic air over the spectral range 700–860 cm −1 for a range of temperatures and pressures (7.5–760 Torr and 208–296 K) appropriate for atmospheric conditions. This new cross-section dataset improves upon the one currently available in the HITRAN and GEISA databases. The second describes a new, preliminary ACE-FTS carbon tetrachloride retrieval that improves upon the v3.0/v3.5 data products, which are biased high by up to ~20–30% relative to ground measurements. Making use of the new spectroscopic data, this retrieval also improves the microwindow selection, contains additional interfering species, and utilises a new instrumental lineshape; it will form the basis for the upcoming v4.0 CCl 4 data product. [ABSTRACT FROM AUTHOR]

High resolution (0.005 cm −1 ) absorption cross sections have been measured for pure propane (C 3 H 8 ). These cross sections cover the 2550–3500 cm −1 region at five temperatures (from 296 to 700 K) and were measured using a Fourier transform spectrometer and a quartz cell heated by a tube furnace. Calibrations were made by comparison to the integrated cross sections of propane from the Pacific Northwest National Laboratory. These are the first high resolution absorption cross sections of propane for the 3 μm region at elevated temperatures. The cross sections provided may be used to monitor propane in combustion environments and in astronomical sources such as the auroral regions of Jupiter, brown dwarfs and exoplanets. [ABSTRACT FROM AUTHOR]

Highlights: [•] Calcium hydride is among the most important diatomic molecules in astrophysics. [•] The A–X and B–X bands of CaH are found frequently in sunspots and cool stars. [•] We recorded high resolution emission spectra of the A2Π–X2Σ and B2Σ–X2Σ transitions of CaH. [•] Rotational analysis and deperturbation of the A2Π and B2Σ excited states have been carried out. [ABSTRACT FROM AUTHOR]

Abstract: Infrared absorption cross sections for methanol, CH3OH, have been determined near 3.4 and 10μm from spectra recorded using a high-resolution FTIR spectrometer (Bruker IFS 125HR) and a multipass cell with a maximum optical path length of 19.3m. Methanol/dry synthetic air mixtures were prepared and spectra were recorded at 0.015cm−1 resolution (calculated as 0.9/MOPD) at a number of temperatures and pressures (50–760Torr and 204–296K) appropriate for atmospheric conditions. Intensities were calibrated using composite methanol spectra taken from the Pacific Northwest National Laboratory (PNNL) IR database. The new measurements in the 10μm region indicate problems with the existing methanol spectroscopic line parameters in the HITRAN database, which will impact the accuracy of satellite retrievals. [Copyright &y& Elsevier]

Abstract: Emission spectra of the A2Π→X2Σ+ and B2Σ+ →X2Σ+ transitions of CaD were produced in a discharge-furnace emission source and recorded with a high resolution Fourier transform spectrometer. The Δv =0 and Δv =−1 sequences up to v′ =3 of the A2Π state and v′ =2 of the B2Σ+ state have been observed and rotationally analyzed. Empirical band constants and Dunham-type constants were determined for all electronic states using N2 Hamiltonians. The equilibrium constants T e, ω e and ω e x e were determined to be 14407.604(2), 957.330(4) and 10.415(2)cm−1 for the A2Π state, and 15751.570(2), 925.840(4) and 12.417(2)cm−1 for the B2Σ+ state, respectively. The equilibrium bond lengths (r e) of the A2Π and B2Σ+ states are 1.977495(3) and 1.963467(6)Å, respectively. [Copyright &y& Elsevier]

Abstract: High resolution infrared absorption cross sections of acetonitrile have been determined from spectra recorded in the 3μm spectral region using a Bruker IFS 125 HR Fourier transform spectrometer (FTS) and a multipass White cell. The eleven synthetic air-broadened acetonitrile spectra were recorded at a resolution of 0.015cm−1 (calculated as 0.9/MOPD (Maximum Optical Path Difference), the Bruker definition of resolution) over a range of different temperatures and pressures that are representative of conditions in the Earth''s atmosphere (50–760Torr and 207–296K). Intensities were calibrated using infrared spectra recorded at the Pacific Northwest National Laboratory (PNNL). These new cross sections will enable satellite retrievals of acetonitrile in the 3μm region from atmospheric spectra recorded by satellite instruments, such as the ACE (Atmospheric Chemistry Experiment)-FTS. [Copyright &y& Elsevier]

Abstract: Infrared absorption cross sections for acetone (propanone), CH3C(O)CH3, have been determined in the 3μm spectral region from spectra recorded using a high-resolution FTIR spectrometer (Bruker IFS 125HR) and a multipass cell with a maximum optical path length of 19.3m. The spectra of mixtures of acetone with dry synthetic air were recorded at 0.015cm−1 resolution (calculated as 0.9/MOPD using the Bruker definition of resolution) at a number of temperatures and pressures (50–760Torr and 195–296K) appropriate for atmospheric conditions. Intensities were calibrated using three acetone spectra (recorded at 278, 293 and 323K) taken from the Pacific Northwest National Laboratory (PNNL) IR database. [ABSTRACT FROM AUTHOR]

Abstract: Emission spectra of WO have been observed in the 4000–35000cm−1 region using a Fourier transform spectrometer. Molecules were produced by exciting a mixture of WCl6 vapor and He in a microwave discharge lamp. A 3Σ− state has been assigned as the ground state of WO based on a rotational analysis of the observed bands and ab initio calculations. After rotational analysis, a majority of strong bands have been classified into three groups. Most of the transitions belonging to the first group have an Ω =0+ state as the lower state while the bands in the second group have an Ω′′=1 state as the lower state. These two lower states have been assigned as X0+ and X1 spin components of the X3Σ− ground state of WO. The third group consists of additional bands interconnected by common vibrational levels involving some very low-lying states. The spectroscopic properties of the low-lying electronic states have been predicted from ab initio calculations. The details of the rotational analysis are presented and an attempt has been made to explain the experimental observations in the light of the ab initio results. [Copyright &y& Elsevier]

Abstract: New high resolution emission spectra of CoH and CoD molecules have been recorded in the 640nm to 3.5μm region using a Fourier transform spectrometer. The bands were excited in a carbon tube furnace by the reaction of cobalt metal vapor and a mixture of H2 or D2 with He at a temperature of about 2600°C. Eight bands were observed for the A′3Φ4–X 3Φ4 electronic transition of CoD, and five bands for the corresponding transition of CoH. The (0,0) bands of the A′3Φ3–X 3Φ3 system were also recorded for both isotopologues, although one of the parity components in the X 3Φ3 sub-state of CoH was found to be perturbed. The A′3Φ3–X 3Φ4 transition was also observed in our spectrum of CoH. In addition, a new [13.3]4 electronic state was found by observing [13.3]4–X 3Φ3 and [13.3]4–X 3Φ4 transitions in the spectrum of CoD. Analysis of the transitions with ΔΩ =0,±1 provided more accurate values of spin–orbit splittings between Ω =4 and Ω =3 components. The ground-state data for both molecules were fitted both to band-constant and Dunham-expansion expressions, and a combined-isotopologue analysis of the X 3Φ4 spin component was carried out using the data for CoH and CoD. The upper states were represented by term values in these analyses because of perturbations, but estimated band constants for them were obtained in separate fits in which ground-state constants were held fixed. [Copyright &y& Elsevier]

Infrared absorption spectra of NH 3 have been obtained at high resolution (0.02 cm −1 ) at seven temperatures between 296 and 973 K. The spectra were recorded using a Bruker IFS 125 infrared Fourier transform spectrometer in the 2400–5500 cm −1 region and empirical lower state energies have been obtained by comparison of line strengths at different temperatures. Using two reference line lists, quantum number assignments have been made for each temperature for between 1660 and 3020 transitions, with J up to 22. The line lists obtained provide accurate line positions as well as intensities and experimental lower state energies at temperatures relevant for modeling the atmospheres of brown dwarfs and exoplanets. [ABSTRACT FROM AUTHOR]

Abstract: Infrared absorption cross sections for acetone (propanone) have been determined in the 830–1950cm−1 spectral region from spectra recorded using a high-resolution FTIR spectrometer (Bruker IFS 125HR) and a multipass cell with a maximum optical path length of 19.3m. The spectra of mixtures of acetone with dry synthetic air were recorded at 0.015cm−1 resolution (calculated as 0.9/MOPD using the Bruker definition of resolution) at a number of temperatures between 194 and 251K and pressures appropriate for atmospheric conditions. Intensities were calibrated using three acetone spectra (recorded at 278, 293 and 323K) taken from the Pacific Northwest National Laboratory (PNNL) IR database. The new absorption cross sections have been combined with previous high spectral resolution results to create a more complete set of acetone absorption cross sections appropriate for atmospheric remote sensing. These cross sections will provide an accurate basis for upper tropospheric/lower stratospheric retrievals of acetone in the mid-infrared spectral region from ACE and MIPAS satellite data. [ABSTRACT FROM AUTHOR]

Abstract: The ACE-FTS is a space-borne Fourier transform spectrometer onboard SCISAT-1. The satellite was launched in August 2003 and since February 2004 the ACE-FTS has been performing solar occultation measurements in order to infer the chemical composition of the terrestrial atmosphere. The individual spectra recorded at the highest limb tangent altitudes (above 160km) are by definition “high sun” spectra and contain no atmospheric contribution. In this work, an empirical solar spectrum covering the 700 to 4430cm−1 spectral range has been constructed from an average of 224,782 individual ACE-FTS solar spectra. Line assignments have been made for about 12,000 lines. The spectrum and two line lists are provided in the supplemental material attached to this work. Due to the excellent noise level achieved in the ACE-FTS solar atlas presented here, numerous weak absorption features are assigned which were not detectable in the ATMOS solar observations. [Copyright &y& Elsevier]

Abstract: Multi-decade atmospheric OCS (carbonyl sulfide) infrared measurements have been analyzed with the goal of quantifying long-term changes and evaluating the consistency of the infrared atmospheric OCS remote-sensing measurement record. Solar-viewing grating spectrometer measurements recorded in April 1951 at the Jungfraujoch station (46.5°N latitude, 8.0°E longitude, 3.58km altitude) show evidence for absorption by lines of the strong ν 3 band of OCS at 2062cm−1. The observation predates the earliest previously reported OCS atmosphere remote-sensing measurement by two decades. More recent infrared ground-based measurements of OCS have been obtained primarily with high-resolution solar-viewing Fourier transform spectrometers (FTSs). Long-term trends derived from this record span more than two decades and show OCS columns that have remained constant or have decreased slightly with time since the Mt. Pinatubo eruption, though retrievals assuming different versions of public spectroscopic databases have been impacted by OCS ν 3 band line intensity differences of ∼10%. The lower stratospheric OCS trend has been inferred assuming spectroscopic parameters from the high-resolution transmission (HITRAN) 2004 database. Volume mixing ratio (VMR) profiles measured near 30°N latitude with high-resolution solar-viewing FTSs operating in the solar occultation mode over a 22 years time span were combined. Atmospheric Trace MOlecucle Spectroscopy (ATMOS) version 3 FTS measurements in 1985 and 1994 were used with Atmospheric Chemistry Experiment (ACE) measurements during 2004–2007. Trends were calculated by referencing the measured OCS VMRs to those of the long-lived constituent N2O to account for variations in the dynamic history of the sampled airmasses. Means and 1-sigma standard deviations of VMRs (in ppbv, or 10−9 per unit air volume) averaged over 30–100hPa from measurements at 25–35°N latitude are 0.334±0.089ppbv from 1985 (ATMOS Spacelab 3 measurements), 0.297±0.094ppbv from 1994 ATLAS 3 measurements, 0.326±0.074ppbv from ACE 2004 measurements, 0.305±0.096ppbv from ACE 2005 measurements, 0.328±0.074 from ACE 2006 measurements, and 0.305±0.090ppbv from ACE measurements through August 2007. Assuming these parameters, we conclude that there has been no statistically significant trend in lower stratospheric OCS over the measurement time span. We discuss past measurement sets, quantify the impact of changes in infrared spectroscopic parameters on atmospheric retrievals and trend measurements, and discuss OCS spectroscopic uncertainties of the current ν 3 band parameters in public atmospheric databases. [Copyright &y& Elsevier]

Abstract: Carbon cycle science by Fourier transform spectroscopy (CC-FTS) is an advanced study for a future satellite mission. The goal of the mission is to obtain a better understanding of the carbon cycle in the Earth''s atmosphere by monitoring total and partial columns of CO2, CH4, N2O, and CO in the near infrared. CO2, CH4, and N2O are important greenhouse gases, and CO is produced by incomplete combustion. The molecular O2 column is also needed to obtain the effective optical path of the reflected sunlight and is used to normalize the column densities of the other gases. As part of this advanced study, ground-based Fourier transform spectra are used to evaluate the spectral region and resolution needed. Spectra in the 3950–7140cm−1 region with a spectral resolution of 0.0042cm−1 recorded at Kiruna (67.84°N, 20.41°E, and 419m above sea level), Sweden, on 1 April 1998, were degraded to the resolutions of 0.01, 0.1, and 0.3cm−1. The effect of spectral resolution on the retrievals has been investigated with these four Kiruna spectra. To obtain further information on the spectral resolution, optical components and spectroscopic parameters required by the future mission, high-resolution solar absorption spectra between 2000 and 15000cm−1 were recorded using Fourier transform spectrometers at Kitt Peak (31.9°N, 111.6°W, and 2.1km above sea level), Arizona, on 25 July 2005 and Waterloo (43.5°N, 80.6°W, and 0.3km above sea level), Ontario, on 22 November 2006 with spectral resolutions of 0.01 and 0.1cm−1, respectively. Dry air volume mixing ratios (VMRs) of CO2 and CH4 were retrieved from these ground-based observations. The HITRAN 2004 spectroscopic parameters are used with the SFIT2 package for the spectral analysis. The measurement precisions for CO2 and CH4 total columns are better than 1.07% and 1.13%, respectively, for our observations. Based on these results, a Fourier transform spectrometer (maximum spectral resolution of 0.1cm−1 or 5cm maximum optical path difference (MOPD)) operating between 2000 and 15000cm−1 is suggested as the primary instrument for the mission. Further progress in improving the atmospheric retrievals for CO2, CH4, and O2 requires new laboratory measurements of the spectroscopic line parameters. [Copyright &y& Elsevier]

Abstract: High resolution infrared emission spectra of ZnH, ZnD, CdH, and CdD have been recorded with a Fourier transform spectrometer. The v =1→0 and v =2→1 bands of ZnH, ZnD, CdH, and CdD, as well as the v =3→2 band of ZnD were observed for the X 2Σ+ ground electronic state. In addition, new rotational spectra have been recorded for CdH and CdD using a tunable far-infrared spectrometer, and pure rotational transitions in the v =1 level of the ground state were measured. The new data were combined with the previous data from diode laser infrared spectra and pure rotation spectra of ZnH/ZnD and CdH/CdD available in the literature. The data from all isotopologues were fitted together using a Dunham-type energy level expression for 2Σ+ states, and Born–Oppenheimer breakdown correction parameters were obtained. The equilibrium rotational constants (B e) of 64ZnH, 64ZnD, 114CdH, and 114CdD were determined to be 6.691332(17), 3.402156(7), 5.447074(18), and 2.750761(6)cm−1, respectively, and the associated equilibrium internuclear distances (r e) are 1.593478(2), 1.593001(2), 1.760098(3), and 1.759695(2)Å, respectively. Simple reduced mass scaling for the spin–rotation interaction constants of ZnH and CdH fully accounted for their isotopologue dependence, and no Born–Oppenheimer breakdown correction was required for these parameters. [Copyright &y& Elsevier]

The gaseous MgD2 molecule has been synthesized for the first time in an electrical discharge inside a high-temperature furnace. The high-resolution infrared emission spectrum of MgD2 was recorded with a Fourier transform spectrometer, and the antisymmetric stretching mode (v3) was detected near 1176.5 cm–1. The v3 band was rotationally analyzed, and the r0 Mg—D bond distance was determined to be 1.700 874(8) Å. [ABSTRACT FROM AUTHOR]

The emission spectrum of gas-phase YbO has been investigated using a Fourier transform spectrometer. Chemiluminescence was observed from excited YbO molecules produced in a Broida-type oven by the reaction of ytterbium metal vapor with N2O. A total of eight red-degraded bands in the range 9800–11 300 cm−1 were recorded at a resolution of 0.04 cm−1. Because of the multiple isotopomers present in the spectra, only three bands were rotationally analyzed. Perturbations were identified in two of these bands and all three transitions were found to terminate at the X 1Σ+ ground electronic state. The electronic configurations that give rise to the observed states are discussed and molecular parameters for all of the analyzed bands are reported. [Copyright &y& Elsevier]