The minimum amount of energy that particles must have in order to react is known as the activation energy. This energy is the minimum barrier that reactant molecules need to overcome to transform into products. Essentially, reactant molecules must have kinetic energy equal to or greater than the activation energy for a chemical reaction to occur.
In particle physics, a similar concept called threshold energy refers to the minimum kinetic energy required for a particle collision to produce a given result. However, in the context of chemical reactions, the term activation energy is the correct one to describe the minimum energy needed for particles to react.
