Calculate a spectrum from ExoMol

Auto-download and compute a SiO spectrum from the ExoMol database ([ExoMol-2020])

from radis import calc_spectrum

s = calc_spectrum(
    1080,
    1320,  # cm-1
    molecule="SiO",
    isotope="1",
    pressure=1.01325,  # bar
    Tgas=1000,  # K
    mole_fraction=0.1,
    path_length=1,  # cm
    broadening_method="fft",  # @ dev: Doesn't work with 'voigt'
    databank=("exomol", "EBJT"),  # Simply use 'exomol' for the recommended database
)
s.apply_slit(1, "cm-1")  # simulate an experimental slit
s.plot("radiance")

Background atmosphere:  Air
Downloading http://www.exomol.com/db/SiO/28Si-16O/EBJT/28Si-16O__EBJT.def
Downloading http://www.exomol.com/db/SiO/28Si-16O/EBJT/28Si-16O__EBJT.pf
Downloading http://www.exomol.com/db/SiO/28Si-16O/EBJT/28Si-16O__EBJT.states.bz2
Downloading http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__H2.broad
Error: Couldn't download .broad file at http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__H2.broad and save.
Downloading http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__He.broad
Error: Couldn't download .broad file at http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__He.broad and save.
Downloading http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__air.broad
Error: Couldn't download .broad file at http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__air.broad and save.
Note: Caching states data to the vaex format. After the second time, it will become much faster.
Reading transition file
Downloading http://www.exomol.com/db/SiO/28Si-16O/EBJT/28Si-16O__EBJT.trans.bz2
Note: Caching line transition data to the vaex format. After the second time, it will become much faster.
.broad is used.
Warning: Cannot load .broad. The default broadening parameters are used.
Calculating Equilibrium Spectrum
Physical Conditions
----------------------------------------
   Tgas                 1000 K
   Trot                 1000 K
   Tvib                 1000 K
   isotope              1
   mole_fraction        0.1
   molecule             SiO
   overpopulation       None
   path_length          1 cm
   pressure_mbar        1013.25 mbar
   rot_distribution     boltzmann
   self_absorption      True
   state                X
   vib_distribution     boltzmann
   wavenum_max          1320.0000 cm-1
   wavenum_min          1080.0000 cm-1
Computation Parameters
----------------------------------------
   Tref                 296 K
   add_at_used
   broadening_method    fft
   cutoff               1e-27 cm-1/(#.cm-2)
   dbformat             exomol-radisdb
   dbpath               /home/docs/.radisdb/exomol/SiO/28Si-16O/EBJT
   folding_thresh       1e-06
   include_neighbouring_lines  True
   memory_mapping_engine  auto
   neighbour_lines      0 cm-1
   optimization         simple
   parfuncfmt           exomol
   parsum_mode          full summation
   pseudo_continuum_threshold  0
   sparse_ldm           auto
   truncation           None cm-1
   waveunit             cm-1
   wstep                0.01 cm-1
   zero_padding         -1
----------------------------------------
/home/docs/checkouts/readthedocs.org/user_builds/radis/envs/master/lib/python3.8/site-packages/radis/misc/warning.py:354: MissingPressureShiftWarning:

Pressure-shift coefficient not given in database: assumed 0 pressure shift

0.07s - Spectrum calculated

<matplotlib.lines.Line2D object at 0x7f848ce01e50>

"""ExoMol lines can be downloaded and accessed separately using
:py:func:`~radis.io.exomol.fetch_exomol`
"""

# See line data:
from radis.io.exomol import fetch_exomol

df = fetch_exomol("SiO", database="EBJT", isotope="1", load_wavenum_max=5000)
print(df)

Background atmosphere:  Air
Downloading http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__H2.broad
Error: Couldn't download .broad file at http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__H2.broad and save.
Downloading http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__He.broad
Error: Couldn't download .broad file at http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__He.broad and save.
Downloading http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__air.broad
Error: Couldn't download .broad file at http://www.exomol.com/db/SiO/28Si-16O/28Si-16O__air.broad and save.
Reading transition file
.broad is used.
Warning: Cannot load .broad. The default broadening parameters are used.
        i_upper  i_lower             A  ...            int  airbrd  Tdpair
0         24300    24299  1.926600e-12  ...  3.923990e-167    0.07     0.5
1          4698     5073  3.431600e-10  ...  2.626438e-202    0.07     0.5
2         24273    24272  1.652000e-10  ...  2.386983e-165    0.07     0.5
3         24301    24300  1.725200e-11  ...  2.947629e-166    0.07     0.5
4         24232    24231  7.675700e-10  ...  1.291448e-164    0.07     0.5
...         ...      ...           ...  ...            ...     ...     ...
249599     3769     1818  2.429700e-04  ...   3.947150e-91    0.07     0.5
249600     8052     6269  1.481800e-02  ...   2.484685e-72    0.07     0.5
249601     8693     6938  1.601100e-02  ...   1.337757e-67    0.07     0.5
249602     8659     6904  1.166600e-02  ...   3.267363e-66    0.07     0.5
249603     7665     5871  3.160000e-03  ...   4.399687e-64    0.07     0.5

[249604 rows x 11 columns]

See the list of recommended databases for the 1st isotope of SiO :

from radis.io.exomol import get_exomol_database_list, get_exomol_full_isotope_name

databases, recommended = get_exomol_database_list(
    "SiO", get_exomol_full_isotope_name("SiO", 1)
)
print("Databases for SiO: ", databases)
print("Database recommended by ExoMol: ", recommended)

Databases for SiO:  ['Kurucz-SiO', 'EBJT', 'xsec-SiOUVenIR', 'SiOUVenIR']
Database recommended by ExoMol:  SiOUVenIR