Search

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]

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]

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: 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: 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]

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]

Abstract: Lorentz pressure-broadening and pressure-induced shift coefficients along with their temperature dependences have been determined for over forty P- and R-branch transitions in the fundamental band of 12C16O broadened with helium. A total of nineteen spectra recorded at various temperatures (+24 to −194°C) in the 2010–2260cm−1 spectral region were analyzed simultaneously using a multispectrum nonlinear least squares fitting technique. The spectra were recorded with the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak. Present results are compared with similar measurements reported recently. [Copyright &y& Elsevier]

Room temperature values for self-broadened and hydrogen-broadened Lorentz halfwidth coefficients, and self and hydrogen pressure-induced shift coefficients have been measured for transitions with rotational quantum number m ranging between -24 and 24 in the 2 ← 0 band of 12C16O. The spectra were recorded with the McMath–Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak. The analysis was performed using a multispectrum nonlinear least squares technique. We have compared our results with similar measurements published recently. [Copyright &y& Elsevier]

This paper describes the status circa 2001, of the HITRAN compilation that comprises the public edition available through 2001. The HITRAN compilation consists of several components useful for radiative transfer calculation codes: high-resolution spectroscopic parameters of molecules in the gas phase, absorption cross-sections for molecules with very dense spectral features, aerosol refractive indices, ultraviolet line-by-line parameters and absorption cross-sections, and associated database management software. The line-by-line portion of the database contains spectroscopic parameters for 38 molecules and their isotopologues and isotopomers suitable for calculating atmospheric transmission and radiance properties. Many more molecular species are presented in the infrared cross-section data than in the previous edition, especially the chlorofluorocarbons and their replacement gases. There is now sufficient representation so that quasi-quantitative simulations can be obtained with the standard radiance codes.In addition to the description and justification of new or modified data that have been incorporated since the last edition of HITRAN (1996), future modifications are indicated for cases considered to have a significant impact on remote-sensing experiments. [Copyright &y& Elsevier]

Abstract: Accurate individual line intensities have been measured for the five interacting bands ν 10, ν 8, ν 7, ν 4 and ν 6 of ethylene-1-13C using a multispectrum nonlinear least squares fitting technique. The measured intensities have been very satisfactorily fit leading to the determination of precise vibrational transition moments. A calculated spectrum accounting for the various rovibrational interactions has been generated. Such a spectrum should be useful for the planetary atmosphere modeling-community. Lorentz self-broadened half-width coefficients have also been measured for nearly 300 transitions in the strongest ν 7 band. [Copyright &y& Elsevier]

Abstract: This study provides the first direct experimental measurements of the off-diagonal relaxation matrix element coefficients for line mixing in air-broadened methane spectra for any vibrational band and the first off diagonal relaxation matrix elements associated with line mixing for pure methane in the ν 2 + ν 3 band of 12CH4. The speed-dependent Voigt profile with line mixing is used with a multispectrum nonlinear least squares curve fitting technique to retrieve the various line parameters from 11 self-broadened and 10 air-broadened spectra simultaneously. The room temperature spectra analyzed in this work are recorded at 0.011cm−1 resolution with the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory, Kitt Peak, Arizona. The off-diagonal relaxation matrix element coefficients of ν 2 + ν 3 transitions between 4410 and 4629cm−1 are reported for eighteen pairs with upper state J values between 2 and 11. The observed line mixing coefficients for self broadening vary from 0.0019 to 0.0390cm−1 atm−1 at 296K. The measured line mixing coefficients for air broadening vary from 0.0005 to 0.0205cm−1 atm−1 at 296K. [Copyright &y& Elsevier]

Abstract: Line positions and strengths of 16O12C18O (628), 18O12C18O (828) and 17O12C18O (728) were measured between 2200 and 7000cm−1 using 22 near infrared (NIR) absorption spectra recorded at 0.01–0.013cm−1 resolution with the McMath–Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak, Arizona. These data were obtained at room temperature using absorption cells with optical path lengths ranging from 2.4 to 385m; the cells were filled with natural and 18O-enriched samples of CO2 at pressures ranging from 0.54 to 252torr. The observed line positions were analyzed to obtain the upper state band centers and rotational constants for 17 bands of 16O12C18O, 19 bands of 18O12C18O and 8 bands of 17O12C18O. The majority of the 18O12C18O and 17O12C18O bands were measured for the first time. In addition, the rotational constants for the lower states 00001, 01101e and 01101f were derived for all three species using the method of combination differences in which the averaged values obtained from the line positions of two or more bands were least-squares-fitted. Rovibrational parameters were also obtained for the 02201e, 02201f, 10002 and 10001 states of 18O12C18O. The line position analysis revealed that transitions of the levels 38⩽ J′⩽46 of the 11111f ←01101f band of 18O12C18O are perturbed. Perturbed transitions were also observed for the 12212←02201 band and in the high-J transitions (J′⩾49) of the 20012←00001 band of 18O12C18O. Band strengths and Herman–Wallis-like F-factor coefficients were determined for 21 bands of 16O12C18O, 25 bands of 18O12C18O and 8 bands of 17O12C18O from least-squares fits to more than 3700 measured transition intensities; band strengths and line positions for 34 of these bands were obtained for the first time. [Copyright &y& Elsevier]

Abstract: Line positions and strengths of 12C16O2 were measured between 4550 and 7000cm−1 using near infrared absorption spectra recorded at 0.01–0.013cm−1 resolution with the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory at Kitt Peak, Arizona. These were retrieved from 42 laboratory spectra obtained at room temperature with five absorption cells having various optical path lengths (from 0.1 to 409m) filled with natural and enriched samples of CO2 at pressures ranging from 2 to 581Torr. In all, band strengths and Herman–Wallis-like F-factor coefficients were determined for 58 vibration–rotation bands from the least-squares fits of over 2100 unblended line strengths; strengths of 34 of these bands had not been previously reported. Band strengths in natural abundance generally ranged from 3.30×10−20 to 2.8×10−25 cm−1/moleculecm−2 at 296K. It was found that the high J transitions (J′⩾61) of the 20012←00001 band centered at 4977.8347cm−1 are perturbed, affecting both measured positions and strengths. Two other interacting bands, 21113e←01101e and 40002e←01101e, were also analyzed using degenerate perturbation theory. Comparisons with corresponding values from the literature indicate that absolute accuracies better than 1% and precisions of 0.5% were achieved for the strongest bands. [Copyright &y& Elsevier]

Abstract: The temperature dependence of air-broadened half-widths are reported for some 500 transitions in the (000)–(000) and (010)–(000) bands of H2 16O using gas sample temperatures ranging from 241 to 388K. These observations were obtained from infrared laboratory spectra recorded at 0.006–0.011cm−1 resolution with the McMath–Pierce Fourier transform spectrometer located at Kitt Peak. The experimental values of the temperature dependence exponents, η, were grouped into eight subsets and fitted to empirical functions in a semi-global procedure. Overall, the values of η were found to decrease with increasing rotational quantum number J. The number of measurements (over 2200) and transitions (586) involved exceeds by a large margin that of any other comparable reported study. [Copyright &y& Elsevier]

Abstract: This paper describes the status of the 2004 edition of the HITRAN molecular spectroscopic database. The HITRAN compilation consists of several components that serve as input for radiative transfer calculation codes: individual line parameters for the microwave through visible spectra of molecules in the gas phase; absorption cross-sections for molecules having dense spectral features, i.e., spectra in which the individual lines are unresolvable; individual line parameters and absorption cross-sections for bands in the ultra-violet; refractive indices of aerosols; tables and files of general properties associated with the database; and database management software. The line-by-line portion of the database contains spectroscopic parameters for 39 molecules including many of their isotopologues. The format of the section of the database on individual line parameters of HITRAN has undergone the most extensive enhancement in almost two decades. It now lists the Einstein -coefficients, statistical weights of the upper and lower levels of the transitions, a better system for the representation of quantum identifications, and enhanced referencing and uncertainty codes. In addition, there is a provision for making corrections to the broadening of line transitions due to line mixing. [Copyright &y& Elsevier]

Abstract: The Lorentz self-broadening (halfwidths) and self-induced pressure-shift coefficients were measured for the first time in the octad region of methane. All spectra were recorded at 0.011cm−1 resolution using the McMath–Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak, Arizona. 12C-enriched CH4 gas samples at room temperature were used, and high signal-to-noise ratios of 2000:1 were achieved. The multispectrum nonlinear least squares fitting technique enabled us to fit simultaneously a total of 10 high-resolution laboratory absorption spectra consisting of six self-broadened and four air-broadened spectra. In this paper, we report the self-broadened widths and self-induced pressure shift coefficients for 1423 transitions belonging to five bands with a maximum J of 16. The numbers of measurements by bands are: 71 for ν 2 +2ν 4, 202 for ν 1 + ν 4, 824 for ν 3 + ν 4, 58 for 2ν 2 + ν 4, and 268 for ν 2 + ν 3. The observed widths varied from 0.045 to about 0.090cm−1 atm−1 at 296K. The measured pressure-shift coefficients had values extending from about −0.020 to −0.005cm−1 atm−1 at 298.3±1.2K. The results obtained for the broadening coefficients in the various bands were compared with each other and with measurements reported in the literature for other methane bands. [Copyright &y& Elsevier]

Abstract: A semiclassical theory based upon the Robert–Bonamy formalism has been developed to explain the experimental measurements of self-broadening, self-induced pressure shift coefficients in the ν1,ν2, 2ν2 bands of H12C14N and the 2ν1 band of H13C14N, as well as the temperature dependences of these parameters with special emphasis on the ν2 band. Our calculations include only electrostatic interactions and neglect the vibrational dependence of the isotropic part of the intermolecular potential, which probably has a weak contribution to the HCN self-shifts for the bands investigated in this study. The agreement between theory and measurements is good in the cases of self-broadening coefficients and their variation with temperature, as well as the self-shift coefficients determined at room temperature. However, the observed temperature dependence of self-shift coefficients in the ν2 band is different from that derived theoretically. [Copyright &y& Elsevier]

We have analyzed the methyl fluoride RQ(J,0) Q branch lines located near 1475 cm−1 using a simultaneous multi-spectrum fitting technique. In this analysis we have used previously recorded diode-laser data in which we collected many data points covering only one or two Q branch lines in a particular run. The analysis consists of simultaneously fitting 57 spectra collected with numerous pressure and path length conditions for all absorption lines. The data are concatenated to create one continuous spectrum of the Q branch. We have determined the intensity and self-broadened widths at 296 K for 23 RQ(J,0) lines. [Copyright &y& Elsevier]

In this article we review ozone spectroscopy from the microwave to the ultraviolet since the release of the 1996 HITRAN database. Uncertainties, deficiencies, areas of potential improvement, and anticipated new spectral line parameters datasets are highlighted. [Copyright &y& Elsevier]