RADIS is a fast line-by-line code for high resolution infrared molecular spectra (emission / absorption, equilibrium / nonequilibrium).

It also includes post-processing tools to compare experimental spectra and spectra calculated with RADIS, or with other spectral codes.


Assuming you have Python installed with the Anaconda distribution you can use pip:

pip install radis

or conda via the conda-forge channel:

conda install radis -c conda-forge

That’s it! You can now run your first example below.

Had a problem or want something different?

First example

Calculate a CO equilibrium spectrum from the [HITRAN-2020] database, using the calc_spectrum() function. Lines are downloaded automatically:

from radis import calc_spectrum
s = calc_spectrum(1900, 2300,         # cm-1
                  pressure=1.01325,   # bar
                  Tgas=700,           # K
                  path_length=1,      # cm
                  databank='hitran',  # or 'hitemp', 'geisa', 'exomol'
s.apply_slit(0.5, 'nm')       # simulate an experimental slit


General description

General details about RADIS features, what RADIS can and can not provide.

Example gallery

Explore the capabilities of RADIS with our examples.

Line-by-line module

Very detailed section on the Line-by-line (LBL) module and how spectra are generated in RADIS (databanks, line profiles, etc.)

The Spectrum object

Manual around the Spectrum object, and how to use it to post-process spectra.

Line-of-sight module

The Line-of-sight (LOS) module for users dealing with line-of-sight experiments. The module allows combination of Spectra such as:

s_line_of_sight = (s_plasma_CO2 // s_plasma_CO) > (s_room_absorption)
HITRAN spectra

The HITRAN spectra database, plotted for every molecule at ambient conditions.

🌐 Try Online

Detailed documentation on the two RADIS online interfaces.

Developer Guide

For developers: how to contribute to RADIS.


References, our published research work, license, and recordings of our conferences.


Detailed documentation of all RADIS modules and classes.


RADIS is built on the shoulders of many state-of-the-art packages and databases. If using RADIS to compute spectra, make sure you cite all of them, for proper reproducibility and acknowledgement of the work! See How to cite?

Q&A Forum

PyPI Downloads Article Documentation Status License Contributors Tests Coverage https://mybinder.org/v2/gh/radis/radis-examples/master?filepath=radis_online.ipynb Gitter Slack