A code to compute the abundance of interstellar species
Astrochem is a code to study the chemistry of a variety of astromical objects (dense clouds, prestellar cores, protoplanetary disks, etc.).
$ astrochem input.ini
Reading input from input.ini.
Reading source model from source.mdl.
Reading reactions network from osu2009.chm... done.
Found 6046 reactions involving 468 species.
Computing abundances in shell 0...
Done with shell 0.
Writing abundances in output files... done.
$
Model parameters are read from simple text files.
[files]
source = source.mdl
chem = osu2009.chm
[phys]
chi = 1.0
cosmic = 1.3e-17
[solver]
ti = 1e-6
tf = 1e7
[abundances]
H2 = 0.5
He = 0.14
N = 2.14e-5
O = 1.76e-4
C(+) = 7.30e-5
S(+) = 8.00e-8
Si(+) = 8.00e-9
Fe(+) = 3.00e-9
Na(+) = 2.00e-9
Mg(+) = 7.00e-9
e(-) = 7.31e-5
[output]
abundances = H3(+),e(-),C(+),CO,HCO(+)
Several chemistry networks are provided with Astrochem. Astrochem's networks format is meant to be easy to read and edit, so networks can be easily adapted to fit your needs.
H + H -> H2
H2 + cosmic-ray -> H2(+) + e(-)
H3(+) + e(-) -> H + H + H
CO + uv-photon -> C + O
Astrochem comes with several handy tools to plot the computed abundances as a function of time, or to identify the main formation or destruction channels for a given species.

Astrochem is fast: problems with networks containing thousands of reactions between hundreds of species can be solved in a few seconds. It is also robust: it has been benchmarked against several other chemistry codes.
Want to learn more about Astrochem? Have a look at the comprehensive documentation manual.
Code by Sébastien Maret. Website by Rémi Prévost.