HITRAN is an acronym for high-resolution transmission molecular absorption database. HITRAN is a compilation of spectroscopic parameters that a variety of computer codes use to predict and simulate the transmission and emission of light in the atmosphere.
The HITRAN group (www.hitran.org , Atomic and Molecular Physics Division, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA) is looking for Postdoctoral associate. Postdoc will be involved in work on the HITRAN and HITEMP compilations. The responsibilities will include construction of the spectral line lists for the molecular species relevant to the modeling of planetary atmospheres. This will include, but is not limited to, collecting available experimental and theoretical data, assessing their quality and creating semi-empirical models for calculating parameters that are not available in the literature. In addition to being co-authors on the widely cited HITRAN and HITEMP papers, the candidates will have an opportunity to work on first-author publications in the field of atmospheric and/or astronomical spectroscopy. Some examples of the publications are given below this ad.
The candidates are expected to have a working experience in the field of molecular spectroscopy (understanding of different types of molecular symmetries, transitions, selection rules, working with Hamiltonians, etc). Experience with FORTRAN and/or Python is required. Proficiency in the English language and good communication skills are required. Candidates will have to be able to work both independently and within a team. Applicants are expected to have completed their PhDs no earlier than July 2011 and be able to start their duties no later than September 1, 2017. In addition, the candidates should have experience in at least three out of the five areas listed below
1. First hand experience with the HITRAN and/or HITEMP databases.
2. Working knowledge of line-shape parametrizations (including the Hartman-Tran profile) and their implementations. Experience with line mixing is a plus.
3. Experience with commonly used spectroscopic programs for fitting and predicting spectra. For instance, LEVEL, SPFIT, PGOPHER, etc.
4. Familiarity with Data Science and its tools. In particular experience in Structured Query Language (SQL). In addition, experience with Django and Apache is a big plus.
5. Proficiency in writing scientific papers, manuals and other types of documentation.
The position is for one year and provides a stipend of about $60,000 per annum. Depending on the performance and the availability of funding, the position may be extended to another year. Medical insurance can be covered.
Applications (with CVs) should be sent to Dr. Iouli E. Gordon (email@example.com). Three reference letters should be sent independently by scientists providing recommendations.
Some relevant publications:
C. Hill, I.E. Gordon, R. V. Kochanov, L. Barrett, J.S. Wilzewski, L.S. Rothman, HITRANonline: An online interface and the flexible representation of spectroscopic data in the HITRAN database, J. Quant. Spectrosc. Radiat. Transf. 177 (2016) 4–14. doi:10.1016/j.jqsrt.2015.12.012.
R.V. Kochanov, I.E. Gordon, L.S. Rothman, P. Wcisło, C. Hill, J.S. Wilzewski, HITRAN Application Programming Interface (HAPI): A comprehensive approach to working with spectroscopic data, J. Quant. Spectrosc. Radiat. Transf. 177 (2016) 15–30. doi:10.1016/j.jqsrt.2016.03.005.
P. Wcisło, I.E. Gordon, H. Tran, Y. Tan, S.-M. Hu, A. Campargue, S. Kassi, D. Romanini, C. Hill, R.V. Kochanov, L.S. Rothman, The implementation of non-Voigt line profiles in the HITRAN database: H2 case study, J. Quant. Spectrosc. Radiat. Transf. 177 (2016) 75–91. doi:10.1016/j.jqsrt.2016.01.024.
J.S. Wilzewski, I.E. Gordon, R. V. Kochanov, C. Hill, L.S. Rothman, H2, He, and CO2 line-broadening coefficients, pressure shifts and temperature-dependence exponents for the HITRAN database. Part 1: SO2, NH3, HF, HCl, OCS and C2H2, J. Quant. Spectrosc. Radiat. Transf. 168 (2016) 193–206. doi:10.1016/j.jqsrt.2015.09.003.
G. Li, I.E. Gordon, L.S. Rothman, Y. Tan, S.-M. Hu, S. Kassi, A. Campargue, E.S. Medvedev, Rovibrational Line Lists for Nine Isotopologues of the CO Molecule in the X1Σ+ Ground Electronic State, Astrophys. J. Suppl. Ser. 216 (2015) 15. doi:10.1088/0067-0049/216/1/15.
G. Li, I.E. Gordon, P.F. Bernath, L.. Rothman, Direct fit of experimental ro-vibrational intensities to the dipole moment function: Application to HCl, J. Quant. Spectrosc. Radiat. Transf. 112 (2011) 1543–1550. doi:10.1016/j.jqsrt.2011.03.014.
I.E. Gordon, L.S. Rothman, G.C. Toon, Revision of spectral parameters for the B- and γ-bands of oxygen and their validation against atmospheric spectra, J. Quant. Spectrosc. Radiat. Transf. 112 (2011) 2310–2322. doi:10.1016/j.jqsrt.2011.05.007.
L.S. Rothman, I.E. Gordon, Y. Babikov, A. Barbe, D. Chris Benner, et al., The HITRAN2012 molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 130 (2013) 4–50. doi:10.1016/j.jqsrt.2013.07.002.
L.S. Rothman, I.E. Gordon, R.J. Barber, H. Dothe, R.R. Gamache, A. Goldman, V.I. Perevalov, S. A. Tashkun, J. Tennyson, HITEMP, the high-temperature molecular spectroscopic database, J. Quant. Spectrosc. Radiat. Transf. 111 (2010) 2139–2150. doi:10.1016/j.jqsrt.2010.05.001.
Three articles that are very helpful in assisting users in learning how to work with new tools and parameters in the HITRAN database have just been published in JQSRT.
1. Article describing structure and working capabilities of HITRANonline (www.hitran.org)
2. Article describing working capabilities of HITRAN Application Programming Interface (HAPI) (www.hitran.org/hapi)
3. Article describing implementation of the Hartmann-Tran profile in the HITRAN database
The HITRAN support e-mail has now been established and our team is ready for questions!
The following updates have been implemented:
1. Adjusting the first allowed rovibrational level to zero (for both isotopologues) as per HITRAN convention.
2. Adding the new bands of the principal isotopologue above 7000 cm-1 based on Barton et al J. Mol. Spectrosc . 325 (2016) 7–12.
3. Updating the MW spectrum of 15N-enriched ammonia with data from the Cologne database.
Until now the UV data for OH in HITRAN was distributed separately from the main line-by-line OH data (those involving transitions in the ground electronic state). These UV data are now implemented in www.hitran.org and can be downloaded through the HITRANonline interface.
The 620-1520 cm-1 region for the principal isotopologue of ethylene has been completely revised based on recent papers by Alkadrou et al, J. Quant. Spectrosc. Radiat. Transf. 182 (2016) 158–171 and 190 (2017) 88.
New bands of the singly 13C-enriched isotopologue were added in the 614-1340 cm-1 region based on papers by Flaud et al, J. Mol. Spectrosc. 267 (2011) 3–12 and 259 (2010) 39–45.
The v9 band region (around 220 cm-1) of diacetylene (C4H2) has been completely replaced with a new line list from Antoine Jolly (LISA, Paris). The updated line list provides new intensity for the lines already existing in the database but also includes numerous hot bands. The v8 band region (around 650 cm-1) 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, Planet. Space Sci. 97 (2014) 60–64. Finally, the v6+v8 region (around 1200 cm-1) was introduced into HITRAN for the first time. This line list was also supplied by A. Jolly.
A new line list of CO (for all six stable isotopologues) was used to update and extend the HITRAN2012 data. The intensities in this list are based on a piece-wise dipole moment function from Li et al, Astrophys. J. Suppl. Ser. 216 (2015) 15. An intensity cutoff of 10-31cm-1/(cm-2 molecule) (in natural abundance of the isotopologues) was used for all IR lines, while a less stringent cutoff was introduced for the MW lines. This extended the amount of lines for the existing bands and allowed introducing new bands up to the sixth overtone. Line positions are based on the semi-empirical potential of Coxon and Hajigeorgiou, J. Chem. Phys. 121 (2004) 2992–3008. For some of the transitions, very high precision measurements (such as with frequency combs) of line positions were used if available. The broadening algorithm was very similar to that of HITRAN2012. Note however that the speed-dependent Voigt data for the first overtone is now completely disentangled from the Voigt data. We also add CO2 and H2 broadening (and its temperature dependence) and shift data from Li et al. Finally, the He broadening and shift of CO lines were also introduced based on extrapolation of the available experimental data.
A considerable amount of existing (in HITRAN2012) bands of the principal isotopologue of ozone were updated, while several new bands were added in different wavelength regions. The update is based on the S&MPO database (Babikov et al, J. Quant. Spectrosc. Radiat. Transf. 145 (2014) 169–196). The data correspond to the October 2016 version of S&MPO. The main feature of this update is the substantially improved intensities of lines in the 2-micron region.
Infrared cross-sections of air-broadened HCFC-22, CFC-12 and CCl4 were updated based on the data from the following papers:
1. HCFC-22: Harrison, Atmos. Meas. Tech. 9 (2016) 2593–2601.
2. CFC-12: Harrison, Atmos. Meas. Tech. 8 (2015) 3197–3207.
3. CCl4: Harrison et al, J. Quant. Spectrosc. Radiat. Transf. (2016), in press.
Finally, the NIR cross-section of pure and air-broadened ethane at 1.68 µm were added based on Reed and Hodges, J. Quant. Spectrosc. Radiat. Transf. 159 (2015) 87–93.
Note that some data for HCFC-22, CFC-12 and CCl4 were available in previous editions of HITRAN originating from different sources. We temporarily retain all of these data, but due to redundancy with the more complete dataset from Harrison et al, a large portion of them will be relegated to the "Alternate" folder on the ftp site upon official release of the HITRAN2016 database
Recent experimental measurements and calculations were employed to update the self- and air- broadening coefficients of line transitions of SO2. A semi-empirical method based on the fit to the available experimental data was used to compute the air-broadening coefficients of SO2. The self-broadening coefficients were updated using scaled semi-classical calculations from Tasinato et al, J. Quant. Spectrosc. Radiat. Transf. 130 (2013) 233–248.
More details about this update can be found in the report by Tan et al.
Transitions of HF with Δv (change in vibrational quantum number) larger than 10 were removed from the database as well as transitions with Δv>8 for DF; likewise for the high overtones of all isotopologues of HCl. This removal was because there were numerical issues in calculating the intensities of these transitions. Medvedev et al, J. Chem. Phys. 143, 154301 (2015) explain how the use of double precision in calculating overtone intensities may lead to numerical errors and that quadruple precision is needed. Additional numerical errors occur depending on the interpolation techniques used for the dipole moment functions as explained in Medvedev et al, J. Mol. Spectrosc. (2016). doi:10.1016/j.jms.2016.06.013.
Transitions of HBr and HI do not appear to be affected by this issue (mainly because they did not have very high overtones) and the linelists for these molecules remain unchanged.
New lines for the 14N218O isotopologue have now been added to the database based on the work of Tashkun et al, J. Quant. Spectrosc. Radiat. Transf. 176 (2016) 62–69. Note that all lines that existed in the HITRAN2012 database were retained, and only new lines were added extending both wavenumber and dynamic range. The linelist for this isotopologue has a new intensity cutoff (under natural abundance) of 10-29 cm/molecule. This makes it temporarily the most complete linelist of all of the isotopologues of N2O, as previously the cutoff of 10-25 cm/molecule was used for all N2O isotopologues.
It was found by Prof. Stephen Ross (UNB, Canada) that 49 lines of the principal isotopologue of HOCl had an incorrect vibrational assignment being attributed to the ν2 band, while in reality they are 2ν3 lines. Also the quantum rotational assignment of the line at 1237.629280 cm-1 was incorrect. All of the assignments were fixed now based on the correct information provided in the original publication: Vander Auwera et al, Journal of Molecular Spectroscopy 204, 36-47 (2000).
The air-induced line shape parameters within the Hartmann-Tran profile formalism were added to the lines in the ν3 band of the principal isotopologue of N2O. These data are based on the recent measurements by Loos et al, JQSRT 151 (2015) 300–309. Also the shifts of the corresponding lines within the traditional Voigt formalism were updated.
The lines of the principal isotopologue of HCN from 3500 to 17586 cm-1 were added to HITRAN for the first time. These data are based on the linelist of Barber et al MNRAS 437 (2014) 1828-1835 which is a mixture of the ab initio intensities and line positions from Harris et al, MNRAS 367 (2006) 400-406, supplemented with empirically-derived line positions wherever possible
Recent experimental measurements and calculations were used to update the self- and air- broadening coefficients (with their temperature dependencies) of all CH3Cl lines. In addition, the 1900-2600 cm-1 spectral region was completely revised, with line positions and intensities calculated based on the recently analyzed Fourier transform spectra in the range of 1900-2600 cm-1 (Nikitin et al, JQSRT (2016) 177, 49–58).
The details of the entire update are given in this linked report
The IUPAC-recommended Hartmann-Tran profile (Tran et al, J. Quant. Spectrosc. Radiat. Transfer 129, 199-203 (2013); J. Quant. Spectrosc. Radiat. Transfer 134, 104 (2014)) is now implemented in the database. At this time it is implemented for self-broadening and shifting in four temperature regimes. Overall, 27 new parameters are added. The hydrogen molecule was chosen as a test case and every line of H2 now has these parameters. The description of how these parameters were derived and details of parametrization are given in the article Wcislo et al. “The implementation of non-Voigt line profiles in the HITRAN database: H2 case study” that is JQSRT, 177, 75-91 (2016).
Note that no such parameters have been added to the HD isotopologue yet. Also we removed 527 transitions of H2 that correspond to high vibrational overtones. This was because there were numerical issues in calculating the intensities of these transitions. Medvedev et al, J. Chem. Phys. 143, 154301 (2015) explain how the use of double precision in calculating overtone intensities may lead to numerical errors and that quadruple precision is needed.
The air-broadening coefficients of HO2 have been updated using an algorithm described in the report by Tan et al, "The air-broadening coefficients of HO2". This algorithm was derived based on recent experimental measurements. For the self-broadening, a default estimate value of 0.3 cm-1/atm was assigned to all transitions.
For H2O2, the measurements of the air-broadening halfwidths from Malathy Devi et al, Appl.Opt. 25, 1844-1847 (1986); Goyette et al, JQSRT 40, 129–134 (1988); and Sato et al, JQSRT 111, 821–825 (2010) were included for the corresponding transitions. The majority of the air-broadened coefficients in the database still have same value of 0.1 cm-1/atm estimated from the measurements of Malathy Devi et al.
Broadening and shift parameters due to the foreign broadeners H2, He, and CO2 have been added to HITRAN for the first time. Currently, the corresponding half-widths, their temperature dependences and pressure-induced shifts by these perturbers for every HITRAN line of SO2, NH3, HF, HCl, OCS and C2H2 can be retrieved from HITRANonline. For HCl-H2 one can also obtain the temperature dependence of the shift. The data are described in the article Wilzewski et al. “H2, He, and CO2 line-broadening coefficients, pressure shifts and temperature-dependence exponents for the HITRAN database. Part 1: SO2, NH3, HF, HCl, OCS and C2H2” that was just published in JQSRT. JQSRT 168, 193–206 (2016).
The values of line positions and lower-state energies for the O atom have been reverted to those given in the HITRAN1996-2000 editions. They originate from L.R. Zink, K.M. Evenson, F. Matsushima, T. Nelis, R.L. Robinson, "Atomic oxygen fine-structure splittings with tunable far-infrared spectroscopy", Astrophysical Journal, Part 2 - Letters 371, L85-L86 (1991). The HITRAN2004-2012 editions used now outdated values from the JPL catalogue, although the reference code still erroneously pointed to the work of Zink et al. The older JPL values have since been fixed in the JPL catalogue, and consequently we reverted back to the more accurate values of Zink et al.
Similar to the error found for the HD molecule mentioned previously, the abundance of the 14N15N isotopologue was incorrectly calculated in the original release of HITRAN2012; this issue has now been fixed in the latest data available from this website.
It was discovered by J. Mendrok (Lulea University of Technology, Kiruna, Sweden) that the abundance of the HD molecule was incorrectly calculated in the original release of HITRAN2012; this issue has now been fixed. The implication was that the intensities of the electric dipole transitions originally reported needed to be multiplied by two, although it did not affect the Einstein-A coefficients.
In addition, a total number 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 K. Pachucki and J. Komasa, “Rovibrational levels of HD”, Phys. Chem. Chem. Phys. 12, 9188-9196 (2010) and the quadrupole moment function of L. Wolniewicz, I. Simbotin, and A. Dalgarno, “Quadrupole Transition Probabilities for the Excited Rovibrational States of H2”, Astrophys. J. Suppl. Ser. 115, 293-313 (1998).
For the purpose of validation, comparisons between the HITRAN database, Kurucz database, and the most recent experimental results have been performed for the H2 and HD transitions. The corresponding report, Comparison of Hydrogen Databases, provides more details on this effort.