The line-by-line portion of the most recent HITRAN2012 editionL.S. Rothman, et al. "The HITRAN 2012 molecular spectroscopic database," JQSRT 130, 4-50 (2013).ontains spectroscopic parameters for 47 gases and associated isotopologues. Continuing the effort of the last five decades, our task has been to improve the accuracy of the existing parameters as well as to add new bands, molecules, and their isotopologues. In this talk we will briefly summarize some of the most important efforts of the past year. Particular attention will be given to explaining the new development in providing line-shape information in HITRAN. There are two important directions in which the database is evolving with respect to line shapes. The first direction is that, apart from the Voigt profile parameters that were traditionally provided in HITRAN, we are able to add parameters associated with many "mainstream" line shapes, including Galatry, speed-dependent Voigt, and the HT profileN.H. Ngo, et al. "An isolated line-shape model to go beyond the Voigt profile in spectroscopic databases and radiative transfer codes," JQSRT 129, 89-100 (2013).ecently recommended by IUPACJ. Tennyson, et al. "Recommended isolated-line profile for representing high-resolution spectroscopic transitions," Pure Appl.Chem. 86, 1931-1943 (2014). As a test case, we created a first complete dataset of the HT parameters for every line of molecular hydrogen in the HITRAN database. Another important development is that in order to increase the potential of the HITRAN database in planetary sciences, experimental and theoretical line-broadening coefficients, line shifts and temperature-dependence exponents of molecules of planetary interest broadened by H₂, He, and CO₂ have been assembled from available peer-reviewed sources. The collected data were used to create semi-empirical models for calculating relevant parameters for every line of the studied molecules in HITRAN.

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Footnotes:

L.S. Rothman, et al. "The HITRAN 2012 molecular spectroscopic database," JQSRT 130, 4-50 (2013).c N.H. Ngo, et al. "An isolated line-shape model to go beyond the Voigt profile in spectroscopic databases and radiative transfer codes," JQSRT 129, 89-100 (2013).r J. Tennyson, et al. "Recommended isolated-line profile for representing high-resolution spectroscopic transitions," Pure Appl.Chem. 86, 1931-1943 (2014)..

We present HITRANonline, an online interface to the internationally-recognised HITRAN molecular spectroscopic database[1], and describe the structure of its relational database backend[2]. As the amount and complexity of spectroscopic data on molecules used in atmospheric modelling has increased, the existing 160-character, text-based format has become inadequate for its description. For example, line shapes such as the Hartmann-Tran profile[3] require up to six parameters for their full description (each with uncertainties and references), data is available on line-broadening by species other than "air" and "self" and more than the current maximum of 10 isotopologues of some molecules (for example, CO₂) can be important for accurate radiative-transfer modelling. The new relational database structure overcomes all of these limitations as well as allowing for better data provenance through "timestamping" of transitions and a direct link between items of data and their literature sources. To take full advantage of this new database structure, the online interface HITRANonline, available at www.hitran.org, provides a user-friendly way to make queries of HITRAN data with the option of returning it in a customizable format with user-defined fields and precisions. Binary formats such as HDF-5 are also supported. In addition to the data, each query also produces its own bibliography (in HTML and BibTeX formats), "README" documentation and interactive graph for easy visualization. This work has been supported by NASA Aura Science Team Grant NNX14AI55G and NASA Planetary Atmospheres Grant NNX13AI59G.

A HITRAN Application Programing Interface (HAPI) has been developed to allow users on their local machines much more flexibility and power. HAPI is a programming interface for the main data-searching capabilities of the new “HITRANonline” web service (http://www.hitran.org). It provides the possibility to query spectroscopic data from the HITRANL.S. Rothman et al. JQSRT, Volume 130, 2013, Pages 4-50atabase in a flexible manner using either functions or query language. Some of the prominent current features of HAPI are: a) Downloading line-by-line data from the HITRANonline site to a local machine b) Filtering and processing the data in SQL-like fashion c) Conventional Python structures (lists, tuples, and dictionaries) for representing spectroscopic data d) Possibility to use a large set of third-party Python libraries to work with the data e) Python implementation of the HT lineshapeN.H. Ngo et al. JQSRT, Volume 129, November 2013, Pages 89–100hich can be reduced to a number of conventional line profiles f) Python implementation of total internal partition sums (TIPS-2011A. L. Laraia at al. Icarus, Volume 215, Issue 1, September 2011, Pages 391–400 for spectra simulations g) High-resolution spectra calculation accounting for pressure, temperature and optical path length h) Providing instrumental functions to simulate experimental spectra i) Possibility to extend HAPI's functionality by custom line profiles, partitions sums and instrumental functions Currently the API is a module written in Python and uses Numpy library providing fast array operations. The API is designed to deal with data in multiple formats such as ASCII, CSV, HDF5 and XSAMS. This work has been supported by NASA Aura Science Team Grant NNX14AI55G and NASA Planetary Atmospheres Grant NNX13AI59G.

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Footnotes:

L.S. Rothman et al. JQSRT, Volume 130, 2013, Pages 4-50d N.H. Ngo et al. JQSRT, Volume 129, November 2013, Pages 89–100w A. L. Laraia at al. Icarus, Volume 215, Issue 1, September 2011, Pages 391–400)

The use of variational nuclear motion calculations to produce comprehensive molecular line lists is now becoming common. In order to produce high quality and complete line-lists in particular applicable to high temperatures requires large amounts of computational resources. The more accuracy required, the larger the problem and the more computational resources needed. The two main bottlenecks in the production of these line-lists are solving the eigenvalue problem and the computation of the Einstein-A coefficients. From the project's recently released line-lists, the number of transitions can reach up to 10 billion evaluated by the combination of millions of eigenvalues and eigenvectors corresponding to individual energy states. For line-lists of this size, the evaluation of Einstein-A coefficients take up the vast majority of computational time compared to solving the eigenvalue problem. Recently, as part of the ExoMol [1] project, we have developed a new program called GPU Accelerated INtensities (GAIN) that utilises the highly parallel Graphics Processing Units (GPU) in order to accelerate the evaluation of the Einstein-A coefficients. Speed-ups of up to 70x can be achieved on a single GPU and can be further improved by utilising multiple GPUs. The GPU hardware, its limitations and how the problem was implemented to exploit parallelism will be discussed.

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J. Tennyson and S. N. Yurchenko. ExoMol: molecular line lists for exoplanet and other atmospheres. MNRAS, 425:21-33, 2012.

Accurate spectroscopic measurements of self- and air-broadened Lorentz half-width and pressure-shift coefficients and their temperature dependence exponents are crucial for the Orbiting Carbon Observatory (OCO-2) mission.D. Crisp, B.M. Fisher, C. O’Dell, et.al., Atmos. Meas. Tech. Discuss 4 (2011) 1-59.e therefore analyzed 73 high-resolution high signal-to-noise spectra of CO₂ and CO₂+air for OCO-2 channels at 1.61 and 2.06 μm. These spectra were recorded at various spectral resolutions (0.004-0.013 cm⁻¹) using two spectrometers (the Kitt Peak FTS in Arizona and the Bruker 125HR FTS at the Jet Propulsion Laboratory in Pasadena, California). Six different absorption cells with path lengths between 0.2 and 121 m were used with gas samples at a range of temperatures (170-297 K). The gas pressures ranged from (0.3-898 Torr for pure sample and 26-924 Torr for mixtures of CO₂ and air with CO₂ volume mixing ratios between 0.01 and 0.4. The cold sample spectra were acquired using a short 0.2038 m straight pass celland a multipass Herriott cell having a 20.941 m total path A multispectrum fitting technique was employed to fit all the spectra simultaneously with a non-Voigt line shape profile including speed dependence and full line mixing. Examples of fitted spectra and retrieved parameters in both CO₂ band regions will be shown. Comparisons of some of the results with other published values will be provided.Research described in this paper are performed at the College of William and Mary, Jet Propulsion Laboratory, California Institute of Technology, NASA Langley Research Center and Connecticut College under contracts and cooperative agreements with the National Aeronautics and Space Administration.html:<hr /><h3>Footnotes: D. Crisp, B.M. Fisher, C. O’Dell, et.al., Atmos. Meas. Tech. Discuss 4 (2011) 1-59.W Research described in this paper are performed at the College of William and Mary, Jet Propulsion Laboratory, California Institute of Technology, NASA Langley Research Center and Connecticut College under contracts and cooperative agreements with the National Aeronautics and Space Administration.

For SO₂ atmospheric characterization in Venus and other Exoplanetary environments, recently we presented Ames-296K line lists for 626 (upgraded) and other 4 symmetric isotopologues: 636, 646, 666 and 828. For CO₂, we reported Ames-296K (1E-42 cm/molecule) and Ames-1000K (1E-36 cm/molecule) IR line lists up to E'=18000 cm⁻¹ for 13 CO₂ isotopologues, including symmetric species 626, 636, 646, 727, 737, 828, 838, and asymmetric species 627, 628, 637, 638, 728, 738. CO₂ line shape parameters were also determined for four different temperature ranges: Mars, Earth, Venus, and higher temperatures. General line position prediction accuracy up to 5000 cm⁻¹ (SO₂) or 13000 cm⁻¹ (CO₂) is 0.01 – 0.02 cm⁻¹. Most transition intensity deviations are less than 5-10%, when compare to experimentally measured quantities. With such prediction accuracy, these SO₂ and CO₂ isotopologue lists are the best available alternative for those wide spectra region missing from spectroscopic databases such as HITRAN and CDMS. For example, only very limited data exist for SO₂ 646/636 and no data at all for other minor isotopologues. They should greatly facilitate spectroscopic analyses in future laboratory or astronomical observations. Our line list work are based on "Best Theory + Reliable High-Resolution Experiment" strategy, i.e. using an ab initio potential energy surface refined with selected reliable high resolution experimental data, and high quality CCSD(T)/aug-cc-pVQ(or Q+d)Z dipole moment surfaces. Note that we have solved a convergence defect on SO₂ Ames-1 PES and further improved the quality and completeness of the Ames-296K SO₂ list by including most recent experimental data into the refinement. We will compare the Ames-296K SO₂ and CO₂ lists to latest experiments and HITRAN/CDMS models. We expect more interactions between experimental and theoretical efforts. Currently the Ames-296K lists are available at http://huang.seti.org/.

Calcium hydride is one of the abundant molecules in the stellar environment, and is considered as a probe of stellar analysisB. Barbuy, R. P. Schiavon, J. Gregorio−Hetem, P. D. Singh  C. Batalha , Astron. Astrophys. Sippl. Ser. 101, 409 (1993).. Ab initio calculations have shown that the electronic excited states of CaH have complex potential curves. It is suggested that the B^2^+ state has an interesting double minimum potential due to the avoided crossingP. F. Weck and P. C .Stabcil, J. Chem. Phys. 118, 9997 (2003).. Such a potential leads to drastic change of the rotational constants when the vibrational energy level goes across the potential barrier. Spectroscopic studies on CaH began in the 1920'sR. S. Mulliken, Phys. Rev. 25, 509 (1925)., and many studies have been carried out since then. Bell et al. extensively assigned the D^2^+-X^2^+ bands in the UV regionG. D. Bell, M, Herman, J. W. C. Johns, and E. R. Peck, Physica Scripta 20, 609 (1979).. Bernath's group has observed transitions in the IR and visible regions and identified their upper states as the A²Σ⁺, B²Σ⁺ and E²Σ⁺ statesA. Shayesteh, K. A. Walker, I. Gordon, D. R. T. Appadoo, and P. F. Bernath, J. Mol. Struct. 695-696, 23 (2004).R. S. Ram, K. Tereszchuk, I. E. Gordon, K. A. Walker, and P. F. Bernath, J. Mol. Spec. 266, 86 (2011).G. Li, J. J. Harrison, R. S. Ram, C. M. Western, and P. F. Bernath Quant. Spectrosc. Rad. Transfer. 113, 67 (2012).A. Shayesteh, R. S. Ram, and P. F. Bernath, J. Mol. Spec. 288, 46 (2013).. We have carried out a laser induced fluorescence (LIF) study in the UV region between 360 and 430 nm. We have produced CaH by using laser ablation of a calcium target in a hydrogen gas environment, then molecules have been excited by a second harmonic pulse of dye laser and the fluorescence from molecules have been detected through a monochromator. Detection of the D²Σ⁺-X²Σ⁺ bands already identified by Bell et al. indicates the production of CaH. In addition, many other bands have been also found and a few bands have been assigned by using the combination differences, the lower state of these bands have been confirmed to the vibrational ground state of X²Σ⁺ state. We have tentatively assigned these bands as the B²Σ⁺ −X²Σ⁺ transition. We will discuss the assignment of these bands, together with the rotational constants comparing with those calculated from the ab initio potential.

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Footnotes:

B. Barbuy, R. P. Schiavon, J. Gregorio-Hetem, P. D. Singh  C. Batalha , Astron. Astrophys. Sippl. Ser. 101, 409 (1993).\end P. F. Weck and P. C .Stabcil, J. Chem. Phys. 118, 9997 (2003). R. S. Mulliken, Phys. Rev. 25, 509 (1925).\end G. D. Bell, M, Herman, J. W. C. Johns, and E. R. Peck, Physica Scripta 20, 609 (1979). A. Shayesteh, K. A. Walker, I. Gordon, D. R. T. Appadoo, and P. F. Bernath, J. Mol. Struct. 695-696, 23 (2004).\end R. S. Ram, K. Tereszchuk, I. E. Gordon, K. A. Walker, and P. F. Bernath, J. Mol. Spec. 266, 86 (2011). G. Li, J. J. Harrison, R. S. Ram, C. M. Western, and P. F. Bernath Quant. Spectrosc. Rad. Transfer. 113, 67 (2012).\end A. Shayesteh, R. S. Ram, and P. F. Bernath, J. Mol. Spec. 288, 46 (2013).

Historically the analysis of the spectrum of water has been a balance between the quality of the data set and the applicability of the Hamiltonian to a highly non-rigid molecule. Recently, a number of different non-rigid analysis approaches have successfully been applied to ¹⁶O water resulting in a self-consistent set of transitions and energy levels to high J which allowed the spectrum to be modeled to experimental precisionSS. Yu, J.C. Pearson, B.J. Drouin et al. J. Mol. Spectrosc. 279, 16-25 (2012)J. Tennyson, P.F. Bernath, L.R. Brown et al. J. Quant. Spectrosc. Rad. Trans. 117, 29-58 (2013). The data set for ¹⁷O and ¹⁸O water was previously reviewed and many of the problematic measurements identifiedJ. Tennyson, P.F. Bernath, L.R. Brown et al. J. Quant. Spectrosc. Rad. Trans. 110, 573-596 (2009) but Hamiltonian modeling of the remaining data resulted in significantly poorer quality fits than that for the ¹⁶O parent. As a result, we have made additional microwave measurements and modeled the existing ¹⁷O and ¹⁸O data sets with an Euler series modelH.M. Pickett, J.C. Pearson, C.E. Miller J. Mol. Spectrosc. 233, 174-179 (2005) This effort has illuminated a number of additional problematic measurements in the previous data sets and has resulted in analyses of ¹⁷O and ¹⁸O water that are of similar quality to the ¹⁶O analysis. We report the new lines, the analyses and make recommendations on the quality of the experimental data sets.

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Footnotes:

SS. Yu, J.C. Pearson, B.J. Drouin et al. J. Mol. Spectrosc. 279, 16-25 (2012)

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Footnotes:

J. Tennyson, P.F. Bernath, L.R. Brown et al. J. Quant. Spectrosc. Rad. Trans. 110, 573-596 (2009), H.M. Pickett, J.C. Pearson, C.E. Miller J. Mol. Spectrosc. 233, 174-179 (2005).

Line lists of CH₄ at high temperatures (up to 900^°C) have been produced between 2500 and 5000 cm⁻¹. This spectral range contains the pentad and octad regions, and includes numerous fundamental, overtone and hot bands. Our method makes use of a quartz sample cell that is heated by a tube furnace. Four spectra are then recorded at each temperature using a Fourier transform infrared spectrometer at high resolution (0.02 cm⁻¹). By combining these four spectra at each temperature, the emission and absorption from the cell and molecules are accounted for, and we obtain the true transmission spectrum of hot CH₄. Analysis of this series of spectra enables the production of line lists that include positions, intensities and empirical lower state energies. We also compare our line lists to the best available theoretical line lists at high temperatures. Whilst our experimental line lists contain fewer lines than theoretical line lists, we are able to demonstrate the quality of our observed spectra by considering our observations as absorption cross sections. This is important at elevated temperatures, when numerous blended lines appear as a continuum.

High resolution absorption spectra of hot ammonia have been recorded in the 2400-5500 cm⁻¹ region and the line lists are presented. This extends our previous work on ammonia in the 740-4000 cm⁻¹ regionR.J. Hargreaves, G. Li and P.F. Bernath. 2011, ApJ, 735, 111^,R.J. Hargreaves, G. Li and P.F. Bernath. 2011, JQSRT, 113, 670nd utilizes our improved cell design that has been successfully applied to methane in a similar spectral region. Transmission spectra were acquired for seven temperatures up to 700^ R.J. Hargreaves, G. Li and P.F. Bernath. 2011, JQSRT, 113, 670a

A highly sensitive experimental set-up (α_min = 10⁻¹⁰ cm⁻¹) has been developed to produce high-temperature infrared spectra of methane in the Tetradecad polyad region (1.67 μm) using cw-CRDS. A continuous flow of methane admixed to argon is initially heated at 1000 – 1500 K and then accelerated to hypersonic speeds in a vacuum chamber before being abruptly stopped by the impact on a planar screen set perpendicular to the flow axis, forming a stationary shock wave detached from the screen (bow shock). The CRD optical beam probes the very hot subsonic zone behind the shock where the gas temperature is close to the stagnation one. Computational Fluid Dynamics calculations have been performed to characterize the post-shock structure of the flow. Spectra reveal a series of new hot bands of fundamental interest for the modeling of highly excited levels of methane.

As one of the most important hydrocarbon prototype molecules, CH₃D’s overtone band in near infrared region has not been well studied. Various methods were used to help identifying transitions from previous cavity ring down spectrum of CH₃D in the near infrared region. Symmetric top molecules’ Hamiltonian diagonal terms for the ground state, perpendicular state and parallel state were simulated by software PGopher. Combination differences were used to find possible pairs of transitions starting from adjacent ground state and ending in same excited states. Also we introduced our temperature controlled spectrum setup for ground state energy and rotational quanta prediction from temperature dependence, and proven to be working well for lower J levels for CH₄. At last, we set up a double resonance system, using two lasers (3.3 and 1.65 μm, respectively) to excite transitions from the same ground state, to provide strong proof for the lower state quanta.

The ExoMol [1] project aims at providing spectroscopic data for key molecules that can be used to characterize the atmospheres of exoplanets and cool stars. Formaldehyde (H₂CO) is of growing importance in studying and modelling terrestrial atmospheric chemistry and dynamics. It also has relevance in astrophysical phenomena that include interstellar medium abundance, proto-planetary and cometary ice chemistry and masers from extra-galactic sources. However there gaps in currently available absolute intensities and a lack of higher rotational excitations that makes it unfeasible to accurately model high temperature systems such as hot Jupiters. Here we present AYTY [2], a new line list for formaldehyde applicable to temperatures up to 1500 K. AYTY contains almost 10 million states reaching rotational excitations up to J=70 and over 10 billion transitions at up to 10 000 cm⁻¹. The line list was computed using the variational ro-vibrational solver TROVE with a refined ab-initio potential energy surface and dipole moment surface.

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J. Tennyson and S. N. Yurchenko. MNRAS, 425:21-33, 2012.

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A. F. Al-Refaie, S. N. Yurchenko, A. Yachmenev, and J. Tennyson. MNRAS, 2015.

Aminoacetonitrile (NH₂CH₂CN) is a potential precursor of the simplest amino acid, glycine and was detected toward SgrB2(N). A. Belloche, K. M. Menten, C. Comito, H. S. P. Müller, P. Schilke, J. Ott, S. Thorwirth, and C. Hieret, 2008, Astronom. & Astrophys. 482, 179 (2008). It is expected that the strongest transitions will be found in the terahertz region so that we have extended measurements up to 1.3 THz. Y. Motoki, Y. Tsunoda, H. Ozeki, and K. Kobayashi, Astrophys. J. Suppl. Ser. 209, 23 (2013). This study gave an accurate prediction of aminoacetonitrile up to 2 THz which is useful for astronomically search. This molecule has a few low-lying vibrational excited states and the pure rotational transitions in these vibrational excited states are expected to found. B. Bak, E. L. Hansen, F. M. Nicolaisen, and O. F. Nielsen, Can. J. Phys. 53, 2183 (1975).We found a series of transitions with intensity of about 30% Y. Motoki, Y. Tsunoda, H. Ozeki, and K. Kobayashi, Astrophys. J. Suppl. Ser. 209, 23 (2013).