Download and pre-process the line lists

If you have access to the hulk cluster at the University of Bern, then most of the pre-processed files are already available at scratch/sigrimm/EXOMOL/. This files can then directly be used for the opacity calculation.

Supported line list databases

HELIOS-K supports line lists from the HITRAN, HITEMP, ExoMol, Kurucz, NIST or VALD databases. Before the line lists can be used, they have to be pre-processed into binary files. This saves in generally memory space and allows HELIOS-K to read the line lists in a more efficient way.

The next section explains the structure of these files and shows how to generate them.

The <species_name>.param file

Each molecular or atomic species, which will be processed by HELIOS-K, needs a <species_name>.param file, which contains all necessary information about the line list database and other parameters. This files can be generated automatically by the tools in HELIOS-K. However, when using a different database, they must be created manually.


An example for HITRAN 2016 H2O is given in the data/01_hit16.param file, which is shown here and available in the repository. An example for HITEMP and ExoMol are also given in the repository files data/01_HITEMP2010.param and data/1H2-16O__BT2.param.

Database = 0
Molecule number = 1
Name = hit16
Number of Isotopologues = 7
#ID Abundance      Q(296K)   g     Molar Mass(g)  partition file :
11 0.997317        174.58    1     18.010565      q1.txt
12 0.002000        176.05    1     20.014811      q2.txt
13 3.718840E-04    1052.14   6     19.01478       q3.txt
14 3.106930E-04    864.74    6     19.01674       q4.txt
15 6.230030E-07    875.57    6     21.020985      q5.txt
16 1.158530E-07    5226.79   36    20.020956      q6.txt
17 2.419700E-07    1027.80   1     20.022915      q129.txt
Number of columns in partition File = 2
Number of line/transition files = 1
Number of lines per file :
Line file limits :
#ExoMol :
Number of states = 0
Number of columns in transition files = 0
Default value of Lorentzian half-width for all lines = 0
Default value of temperature exponent for all lines = 0
Version = 0


  • Database: Indicate which database format to use.

  • 0 = Hitran or HITEMP

  • 2 = ExoMol

  • 30 = Kurucz atomic database

  • 31 = NIST atomic database

  • Molecule number: This is optional and follows an old HELIOS-K version.

  • Name: name of the line list files.

  • Number of isotopologues in the line list files.

  • For each isotopologue:

    • ID: for Hitran and HITEMP the same as the first three digits in the *.par files e.g. 11 for 1H2-18O, or 2A for 18O-13C-17O. For ExoMol no meaning.

    • Abundance, only relevant for more than one isotopologue.

    • Reference partition function value. For ExoMol no meaning.

    • Molar mass in g.

    • Name of the partition function file.

  • Number of columns in the partition function file.

  • Number of line/transition files.

  • Line by line, the number of molecular/atomic lines in each line/transition file.

  • Line by line, the wavenumber range of each line/transition file, must have one entry more than the number of line/transition files to cover all lower and upper range limits.

  • Number of states in ExoMol *.statesfiles. For other databases no meaning.

  • Number of columns in ExoMol *.transfiles. For other databases no meaning.

  • ExoMol default value of Lorentzian half-width. For other databases no meaning.

  • ExoMol default value of temperature exponent. For other databases no meaning.

  • Version of the line list.