# Gibbs free energy=potential free energy? (Transition state theory)

Online I found the plot Gibbs free energy vs. reaction coordinate:

https://en.wikipedia.org/wiki/Transition_state_theory

and on many books I found the plot potential energy vs. reaction coordinate (e.g. page 237 Atkins, Physical Chemistry for the Life Sciences, 2nd Ed).

In the first case activation energy is defined as $\Delta G$, whereas in the second case is defined as difference of potential energy.

Thus is the Gibbs free energy a potential energy?

Thank you very much.

• Gibbs free energy is defined for system/ensemble of particles. Potential energy surface is generally calculated to a single molecular complex. They are not in the same realm, but can estimated.
– Greg
Mar 13 '17 at 13:06