easyCHEM documentation
======================
Welcome to the **easyCHEM** documentation. easyCHEM is a Python package for calculating chemical abundances in exoplanet atmospheres, assuming equilibrium chemistry and including condensation. Ancillary outputs are the atmospheric adiabatic temperature gradient and mean molar mass. easyCHEM is a clone of
the equilibrium chemistry part of `NASA's CEA `_ code, written from scratch
and with numerical stability in mind. In particular, the code implements the
equations described in `Gordon & McBride (1994) `_ and makes use of `LAPACK's dgesv routine `_ for fast matrix inversion. Since we incorporated the ``dgesv`` source code into easyCHEM, users do not require external math libraries.
easyCHEM's thermodynamic input data is based on the NASA Glenn thermodynamic input database, which can be accessed `here `_. Additional NASA polynomials have been obtained from `Lodders & Fegley (2002) `_, `Visscher et al. (2010) `_, or were derived from thermodynamic data in the `NIST-JANAF database `_ and condensate data listed in `Robie et al. (1978) `_. The thermodynamic data of the condensates was extended to low temperatures (60 K) using the method described in Appendix A.2 of `Mollière et al. (2017) `_.
**To get started with some examples on how to run easyCHEM, see our** `"easyCHEM tutorial" `_.
**For easyCHEM's reproduction of the SONORA equilibrium chemistry grid see** `here `_. This notebook was provided and is maintained by easyCHEM contributor Channon Visscher.
easyCHEM is available under the MIT License, and its base Fortran implementation was described in
`Mollière et al. (2017) `_. It was benchmarked against the CEA code, leading to identical results. It was also compared to the equilibrium chemistry codes used for the ATMO and Exo-REM atmospheric models, again showing excellent agreement, see `Baudino et al. (2017) `_.
Please cite `Lei & Mollière (2025) `_ when making use of easyCHEM in your research.
.. _contact: molliere@mpia.de
This documentation webpage contains an `installation guide `_, a
`tutorial `_, `community guidelines for contributions `_, and an `API documentation `_.
Developers
___________
- Elise Lei and Paul Mollière
Contributors
____________
- Channon Visscher
.. toctree::
:maxdepth: 3
:caption: Content:
content/installation
content/notebooks/getting_started
content/notebooks/easychem_sonora_2025
content/contributing
.. toctree::
:maxdepth: 2
:caption: Code documentation