In Kohn-Sham DFT, the Coulomb potential, which is a component of the Kohn-Sham potential, is given by:
v_H(\mathbf{r}) = \int \frac{\rho(\mathbf{r'})}{|\mathbf{r}-\mathbf{r'}|}d\mathbf{r'}
where \rho(\mathbf{r'}) is the electron density.
For molecular systems with exponential densities...