intrinsic activation energy, \(E_{\text{a,i}}\)

https://doi.org/10.1351/goldbook.I03134
If \(E_{\text{a,1}}\) and \(E_{\text{a,- 1}}\) are the @[email protected] for a reaction in forward and reverse directions, the lesser of the two is sometimes called the intrinsic @[email protected] energy. It is the @[email protected] energy for the reaction in the exothermic direction.
Source:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 170 [Terms] [Paper]