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

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

In chemistry and physics, activation energy is the minimum amount of
energy that must be provided for compounds to result in a chemical
reaction.[1] The activation energy (Ea) of a reaction is measured in
joules per mole (J/mol), kilojoules per mole (kJ/mol) or kilocalories
per mole (kcal/mol).[2] Activation energy can be thought of as the
magnitude of the potential barrier (sometimes called the energy
barrier) separating minima of the potential energy surface pertaining
to the initial and final thermodynamic state. For a chemical reaction
to proceed at a reasonable rate, the temperature of the system should
be high enough such that there exists an appreciable number of
molecules with translational energy equal to or greater than the
activation energy. The term "activation energy" was introduced in 1889
by the Swedish scientist Svante Arrhenius.[3]