# Potential energy versus reaction coordinate (graph of Gibbs free energy)

Does the potential energy scale in the above mentioned graph measure the Gibbs free energy of the system?

As the system always tries to achieve a minimum of free energy and chemical reactions are taking place can be considered a non-mechanical work (I'm not sure of it, as the system isn't in a state of chemical equilibrium if a reaction is taking place), potential energy should represent Gibbs free energy.

If not, how should I understand the potential energy of a reaction mixture?

$Z = e^{- \frac{F}{kT}} = \sum_i e^{- \frac{E_i}{kT}}$