# Classical density functional theory
This section explains the implementation of the core expressions from classical density functional theory in $\text{FeO}_\text{s}$.

```{eval-rst}
.. toctree::
   :maxdepth: 1

   euler_lagrange_equation
   functional_derivatives
   solver
   derivatives
   enthalpy_of_adsorption
   pdgt
```

It is currently still under construction. You can help by [contributing](https://github.com/feos-org/feos/issues/70).