chemical activation

https://doi.org/10.1351/goldbook.C01017
When some of the energy required for a reaction is provided by a preceding exothermic chemical reaction there is said to be chemical
activation
. For example, in the scheme:
some or all of the energy required for X to decompose is provided by the first reaction.
Source:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 158 [Terms] [Paper]