dataesr/scientific-paragraphs-categorization huggingface dataset:
However, they are very helpful in assigning experimental spectra and invaluable in high-temperature simulations and will be considered for inclusion in a future edition of the HITEMP database  [278]. The theoretical background and the set of programs used for both the energy and intensity fittings in the analysis of Malathy Devi et al. are described in Ref. [426]. Along with the positions and intensities, line-shape parameters were measured for a large number of transitions (over 840 Lorentz self-broadened half width coefficients, 620 self-shift coefficients, 185 speed dependence parameters, and collisional line-mixing parameters for 10 A þ Adoublet transitions) in the 2ν 4 , ν 1 and ν 3 bands, and those measurements are reported in a separate article  [425]. As mentioned in the analysis of positions and intensities  [426] , the parameters in the pentad region are important for the exploration of chemistry and dynamics on Saturn using the existing Cassini/VIMS observations.
The results reported in Refs. [425, 426]  (which have appropriate supplementary materials) are applicable to a variety of remote-sensing studies including the analyses of the near infrared data of Jupiter from the Juno mission and ESA's Jupiter Icy Moons Explorer (JUICE). Creation of a line list of PH 3 in the pentad and octad regions is in progress and is expected to be available as an update to the HITRAN2016 database.
This is fixed in HITRAN2016. The air-broadening coefficients of hydrogen sulfide (H 2 S) in the HITRAN database were set to a constant value, γ air ¼ 0. 0740 cm À 1 atm À 1 at 296 K, for most of the transitions (since HITRAN2004  [3] ) based on the average value of available experimental data while just a few half widths were based on experimental values. For HITRAN2016, a thorough survey of measurements of both the airbroadening and self-broadening coefficients of H 2 S has been made  [435] [436] [437] [438]. The report by Tan et al. [439]  describes the results in more detail. In brief, a slow decrease of the air-(and self-) broadening coefficients with increasing ( J 00 þ 0. 2K a 0 0 ) lower-state quantum number combination can be seen in Fig. 24. The vibrational dependence of the broadening parameters is neglected and we use the semi-empirical method based on the linear fit to the available experimental data to compute both air-and self-broadening coefficients of H 2 S for all the isotopologues.
[469] , and the results of ab initio based calculations including cold and hot bands in the range 0-6000 cm À 1 can be found in the TheoReTS database  [205]. These calculations agree well with the new HITRAN2016 line list and experimental PNNL spectra  [314]  in the 10mm region. New bands of 12 C 13 CH 4 are included in the new version of the database. More precisely, the new parameters which were derived from high-resolution Fourier transform spectra are those of the ν 10 , ν 8, ν 7, ν 4, ν 6 bands, which absorb in the 615-1339 cm À 1 spectral region  [472, 473]. Their accuracy can be estimated to be of the order of 0. 6 Â 10 À 3 cm À 1 for the positions  [473]  and 4% for the intensities  [472]. The broadening parameters were determined in the same fashion as for the principal isotopologue described above.
C 4 H 2 (molecule 43) The ν 9 band region (around 220 cm À 1 ) and the ν 8 band region (around 650 cm À 1 ) of diacetylene, C 4 H 2 , is important in interpreting Titan  [488]  observations. The ν 9 band region has been completely replaced with a new line list derived from a combined analysis presented in Refs. [488, 489]. The updated line list provides new intensity for the lines already existing in the database but also includes numerous hot bands. The ν 8 band region was updated by scaling the intensities of all the lines in that region by a factor of 0. 8 based on the recommendation given in Jolly et al. [489]. Finally, the ν 6 þν 8 region (around 1200 cm À 1 ) was introduced into HITRAN for the first time based on the predictions from the global analyses. This band is important in astrophysics as it has been observed in the atmosphere of Titan and the preplanetary nebula SMP LMC 11 with the Spitzer Infrared Spectrograph  [490].
In addition, a total of 7195 electric quadrupole transitions of the HD molecule have been calculated and added to the HITRAN line list. The calculation was carried out using the energy levels from the work by Pachucki and Komasa  [491]  and the quadrupole moment function of Wolniewicz et al. [492]. In HITRAN2016, 527 transitions of H 2 that correspond to high vibrational overtones were removed. This was because there were numerical issues in calculating the intensities of these transitions. Refs. [340, 341]  explain how the use of double precision in calculating overtone intensities may lead to numerical errors and that quadruple precision is needed. Only a default value of the broadening parameter for the Voigt profile was given (the same for all the lines) in HITRAN2012. In HITRAN2016, a complete dataset of the line-shape parameters for the Hartmann-Tran profile is provided for self-perturbed H 2  [6].
This dataset was determined from the analysis of H 2 experimental spectra. According to the new recommendation adopted in HI-TRAN, these line-shape parameters are stored separately for four different temperature ranges, see Ref. [6]. For the lines and conditions for which experimental spectra are not available, the lineshape parameters were extrapolated. In the near future we plan to extend HITRAN with the HT line-shape parameters for H 2 perturbed by helium, which will be based on experimentally validated ab initio calculations  [493].
SO 3 (molecule 47) Sulfur trioxide (SO 3 ) occurs naturally in volcanic emissions and hot springs  [494]. It is also a pollutant emitted by smoke stacks and other industrial exhausts  [495]. In the terrestrial atmosphere, SO 3 rapidly forms sulfuric acid with its association with acid rain. SO 3 is a constituent in the atmosphere of Venus  [496]. Recently, Zhang et al. [497]  have indicated that measurements of the abundances of SO 3 in the lower thermosphere of Venus can answer important questions related to sulfur chemistry. The spectroscopic study of sulfur oxides can also provide insight into the history of the Earth's atmosphere  [498]  and hence modeling of Earth-like planets. SO 3 was included for the first time in the 2012 HITRAN edition. This entry was based on the experimental data of Maki and coworkers  [499] [500] [501] [502]  with relative transition intensities scaled by the absolute values computed ab initio by Underwood et al.
[503]. Also included were 25 pure-rotation transitions observed by Meyer et al. [504]  for which the ab initio intensities of Underwood et al. [503]  were used. SO 3 is a planar, non-polar molecule but with sufficient rotational excitation that the molecule can distort and undergo pure-rotational transitions. A hybrid, empirical ab initio rotational line list for 32 S 16 O 3 has been constructed for this edition of the database. For this, the ground-state rotational constants and centrifugal distortion parameters were taken from the fits to their infrared spectrum given by Ref. [502] ; these were used to generate a set of vibrational ground-state rotational energies for J up to 85. To ensure that the extrapolation to high-J states is reasonable, a comparison was made between these energy levels and those calculated variationally by Ref.
The cross-sections come from high-resolution laboratory observations, predominantly from Fourier transform spectrometers. Some of these measurements include small negative values, which for the HITRAN-formatted cross-sections were substituted by zeroes; in these cases we provide all the original cross-sections in a supplementary "Alternate" folder, because the negative values provide the user with some information about the noise level in the measurements. The HITRAN2012 edition of the database contained cross-sections for about fifty gases. For the HITRAN2016 edition we have increased the amount of gases almost six fold by adding new data in the infrared spectral range. A dedicated paper detailing this update will be published separately. Here we only provide a brief summary and overview tables.
Around 220 molecules of atmospheric, industrial, and remote sensing interests were taken from the quantitative spectroscopy PNNL (Pacific Northwest National Laboratory) database, described in Sharpe et al. [314]. This compilation was updated with 55 molecules from more recent work of Johnson et al. [519]. Twelve of these 55 molcules are new to PNNL. Spectra for these molecules will be indispensable, particularly for biomass burning detection. The PNNL database contains calibration-quality composite spectra given at atmospheric pressure and three temperatures (5 °C, 25 °C, and 50 °C). All these cross-sections were measured using the FT-IR technique with 0. 112 cm À 1 spectral resolution on a Bruker IFS 66v/S spectrometer. In addition, a large portion of new molecules of atmospheric interest was taken from the 2013 review by Hodnebrog et al.
The summary on the new and updated compounds divided by categories is presented in Table  9. These categories are implemented in HITRANonline for the convenience of users to browse the data. This summary does not include those compounds that Fig. 27. Update for cross-sections for acetaldehyde. Comparison of three temperature-pressure cross-section sets from PNNL  [314]  (update) with corresponding data from HITRAN2012 (Ref. [541] ).
Molecule CAS ♦ Wavenumber range (cm À 1 ) T (K) P (Torr) Resolution (cm ♦Chemical Abstracts Service number *Data from these sources can be found in the alternate folder. were not updated. For instance, there are no new UV cross-sections that were added; therefore molecules that had only UV cross-sections in HITRAN2012 are not included in this table. In Fig. 27  we show an example of the update for the acetaldehyde molecule (CH 3 CHO). The new data were taken from the PNNL database  [314] , while the data from HITRAN2012 were originally from Tereszchuk and Bernath  [541]. Sixteen cross-section temperature-pressure sets from Ref. [541]  are presented in HI-TRAN2012 in the 2400-3400 cm À 1 spectral range. These crosssections were calibrated using the PNNL data  [541]  and thus are in a good agreement with the update, in particular for absorption between 6.
0 Â 10 À 21 and 1. 0 Â 10 À 19 cm 2 molecule À 1. For this molecule, the new update extends the temperature range up to 323 K and the wavenumber range from 510 to 6500 cm À 1. The update includes stronger features in the mid-infrared which were absent in HITRAN2012. The data from Ref. [541]  are also retained in the new HITRAN release. In Table  10  the updates to the cross-sections of the molecules already existing in HITRAN2012 are presented. High-quality data were taken from different sources for the ranges which were either absent or covered insufficiently. Updates for molecules that were not previously in HITRAN are presented in Table  11. In both Table  10  and Table  11  we give total ranges for the wavenumber, pressure, temperature, and resolution. Each line in both of the tables summarizes all updated cross-sections for the given molecule, including those relegated to the alternate folder.
Collision-induced absorption Collision-induced absorption (CIA) was first introduced into HITRAN in the 2012 edition and was largely based on the data collected in Richard et al. [586]. This section of the database is accessible through (www. hitran. org/cia). CIA refers to absorption by transient electric dipoles induced by the interaction between colliding molecules. Due to the short life-time of collision complexes, this typically leads to broad absorption features underlying the much sharper lines due to absorption by isolated molecules. As CIA arises from binary collision complexes, the intensity scales with the number densities of both the absorber and the perturber, i. e. , with the square of the pressure at constant volume mixing ratio. To be completely explicit, the transmittance at wavenumber ν, τ abs-pert (ν), is related to the collision-induced cross section tabulated in the HITRAN CIA section, k abs-pert (ν), through ⎡ ⎣ ⎤ ⎦ τ ν νρ ρ - () = () ( ) - - L ln k , 10 abs pert abs pert abs pert where ρ abs and ρ pert are the number densities of the absorber and perturber, respectively, and L is the path length.
Molecular oxygen 1. 27-mm band The CIA data for the 1. 27-mm band (corresponding to  O 2  have been revised in the current release of HITRAN. In this region, CIA is stronger whereas magnetic dipole lines are weaker when compared to the oxygen A-band. Hence, under atmospheric conditions, CIA contributes significantly to the absorption in the 1. 27-mm band. X 3 Σ - g (v ¼ 0) -a 1 Δ g (v ¼ 0)) of All data included for this transition are taken from the experiment by Maté et al. [587] , recorded using a Fourier transform spectrometer. Data recorded for pure O 2 can be found in the O 2 À O 2 file. These data have been corrected for an error in HI-TRAN2012, which accidentally contained O 2 À Air spectra. Data recorded for air mixtures of 21:79 O 2 :N 2 can be found in the O 2 À Air file, which is described above.
In the previous version of HI-TRAN, data for such mixtures could be found in the O 2 À N 2 file, but these have been moved to the O 2 ÀAir file to stress that these also include O    Fig. 30. Groups of related parameters such as those relating to the HT profile in different temperature regions are selected from a separate set of overlay panels in the HITRANonline interface. When one or more temperature groups are chosen, the three "Common parameters" are also automatically selected. Conversely, these common parameters are removed from the selection when no temperature group is chosen for this profile. Different broadening species are presented on separate panels, and may be selected from the labeled tabs at the top of the overlay. and Newnham for this band  [588]. The data previously provided in this band for O 2 :N 2 mixtures contained magnetic dipole lines due to O 2 monomer absorption.
Oxygen A band in air Collision-induced absorption in the oxygen A band is also of atmospheric interest. In spite of the smaller contribution of CIA in this band, relative to the much stronger magnetic dipole lines, CIA is significant for high-accuracy measurements including airmass calibration of the OCO-2 instrument  [589]. The HITRAN CIA database already contained data for O 2 À O 2 and O 2 À N 2 from Tran et al. [253] , valid for temperatures between 200 and 300 K. For convenience, we now also provide the spectrum for O 2 À Air, obtained by combining the available O 2 À O 2 and O 2 À N 2 data. In the alternate folder, we now also include O 2 À Air data from Drouin et al. [252]  obtained in a multispectrum fitting approach. Line-byline parameters determined in the same multispectrum fit, are also available in HITRAN2016.
6. Global data and software 6. 1. Database structure and interface (www. hitran. org) Since June 2015, users have been able to access the HITRAN line-by-line data not only by downloading them in the traditional ASCII 160-character (. par) format from the ftp site, but also through the easy-to-use interface HITRANonline, available at www. hitran. org. Cross sections can also be accessed through this dynamic interface, while CIA and aerosols sections of the database are also accessible, though so far only as static files. This new tool (described in Hill et al. [2] ) allows custom filtering and selection of molecules and their isotopologues in the wavenumber region of interest. The default output format is still. par, but users are given an opportunity to create their own, customized output formats, including the HDF5 format widely used by NASA scientists.
The flexibility of the formats is achieved due to the fact that the database is cast into a relational format  [236] : it is now a compilation of tables of parameters and metadata that are interconnected and searchable using Structured Query Language (SQL) (see Refs. [2]  and  [236]  for details). This new flexible database format offers many advantages over the static fixed-width ASCII files. Indeed, we have now introduced non-Voigt line shapes  [6] , broadening parameters by perturbing gases other than air or self  [4] , and other parameters that are important for accurate atmospheric retrievals. Other advantages of the new structure include allowing more significant figures (for instance, important for line positions of the MW transitions) and checks on data integrity. Further advantages include immediate access to the references for every parameter (including the automatic generation of bibliography in both HTML and BibTeX format), generation of interactive plots of retrieved line-by-line and cross-section data (with full features such as zoom, etc.
HITRAN application programming interface (HAPI) The HITRAN Application Programming Interface (HAPI) is a free open source Python module (library) which provides a set of tools for working with structured spectroscopic data from different sources. It is described in detail in Ref. [5]. Here we give a brief overview of its features. Originally created as an extension of the HITRANonline web interface  [2]  to allow users sophisticated calculations and manipulations with the HITRAN data on their computers, HAPI can handle user-supplied custom data in a flexible way and fully supports the HITRANonline data scheme and formats of the HI-TRAN  [1]  database. The principal aim of HAPI is facilitating physically-sound interpretation of observations and more realistic models for a wide variety of applications such as astrophysics, planetary science, climate simulations, remote sensing, theoretical spectroscopy, and data mining.
Having such a tool is important in particular to prevent possible errors in radiative-transfer calculations caused by misuse of spectroscopic tools and databases (see example discussed in Ref. [636]  for instance). The HAPI package can be obtained via the HITRANonline website (http://hitran. org/hapi) or from the Zenodo community (http://zenodo. org/communities/hapi/about/). The current version (1. 1) is distributed under a permissive open source license (MIT). Additional links can be found on the official HITRAN site. HAPI consists of two major parts. First, it has a simple built-in database management system written in pure Python, which gives a capability of data processing and filtering. Second, HAPI incorporates a set of tools for spectra simulation accounting for the temperature, pressure, optical path length, and instrument properties.
Total internal partition sums (TIPS) Total internal partition sums (TIPS) were determined for all molecules and isotopologues in HITRAN2016 and for a number of isotopologues of molecules of interest in planetary atmospheres. The current TIPS data are calculated in one-degree steps from 1 K to T max , where T max is determined separately for each isotopologue based on convergence of the partition sums. The TIPS are comprised of updated calculations and values from previous studies of TIPS  [112, [637] [638] [639]. The updates can be grouped into several categories: improvements in ab initio calculations that allow direct sums over energy levels, improved Q vib values using the anharmonic approximation  [640] , and calculations for new molecule/ isotopologues in the HITRAN database. The updates that were made for isotopologues in this edition of HITRAN are listed in Table  13.
Conclusions The improvements, expansions and new structure in the new HITRAN database release have been elaborated upon. For the lineby-line data, improved line position, intensity, and line-shape parameters for many of the previously existing molecules and isotopologues have been introduced. Many new lines/bands have been added for different molecules and their isotopologues allowing for a more complete database (for atmospheric applications) and for the expansion of the spectral coverage of the existing line lists. Additionally, HITRAN continues evolving in terms of structure and scope. A new relational database structure has been established  [2]  that enabled significant expansion of the amount of important spectroscopic parameters provided in the database. Literally dozens of new parameters have been introduced that allow accommodation of non-Voigt line shapes  [6] ; flexible representation of broadening parameters and their temperature dependencies; broadening and shift of spectral lines due to pressure of gases dominant in planetary atmospheres  [4]  (namely, H 2 , He and CO 2 ).
This extensive expansion of the database would have been very impractical in the old fixed-length ASCII format of previous HITRAN editions. An interface on the internet has also been established (www. hitran. org) that provides the diverse group of HITRAN users with much power to filter, extract, plot, and query the database. Even more power has been given to the user through the introduction of the HITRAN Application Programming Interface (HAPI)  [5]. HAPI is currently a set of Python libraries which not only allows users to download data from the database but also to carry out: 1) single-layer absorption calculations at different thermodynamic conditions, accounting for an instrument function, new line shape parametrizations, perturbing gas or gases, etc, 2) extended functionality provided by custom functions, line lists and partition sums.
Several new molecules and isotopologues have been added to the line-by-line portion of the compilation, which improve modeling of the absorption of the terrestrial atmosphere and beyond. One of the main highlights of the new edition is the monumental expansion of the cross-sectional part of the database which increased (in terms of amount of gases) about six-fold and now features over 300 species. These cross-sections can also be accessible through www. hitran. org where they are divided into categories for easy browsing. Aerosols and collision induced absorption datasets have also been revised and extended. The compilation is free and can be accessed through www. hi tran. org. We recommend citing this article when using the HI-TRAN2016 data. If an update to a certain molecule is announced on the website and is being used, then we encourage users to cite when they downloaded the data.
Future work While HITRAN continues to be an international standard for reference spectroscopy for atmospheric and planetary gases, there is still substantial room for improvement. In many subsections throughout the paper we mention the avenues for improvements for individual molecules, but they are really just the tip of the iceberg. The studies of the terrestrial atmosphere require further improvements to the existing parameters and what is more challenging: population of the dataset of the non-Voigt line-shape parameters. As was discussed above, the amount of measurements and calculations of the parameters obtained using the recommended HT profile are scarce and it will take time before a majority of HITRAN lines will have these parameters provided. Also, we remind experimentalists and theoreticians to take extreme care when fitting to these parameters to avoid correlations.
Moreover, all of the current updates are in the IR part of the spectrum and another substantial update is needed for the UV cross-sections. A massive revision and expansion of the CIA data is planned for the near future. Structure and the tools provided with the database are also a very important part of the HITRAN database. We plan further improvements to the documentation for the HITRANonline interface and the development of video tutorials. Finally, development of an interactive interface is planned for HAPI, for which video tutorials will also be created.