## activation

Also contains definition of: degree of activation
https://doi.org/10.1351/goldbook.A00093
This word is used in different senses:
1. Input of external energy into a chemical system is said to bring about activation of the system.
2. An added substance that increases the rate of a catalysed reaction is known as an activator, and the effect is called activation. The degree of activation $$\varepsilon_{\text{a}}$$ is defined by: $\varepsilon_{\text{a}}=\frac{v\,-\,v_{0}}{v_{0}} = \frac{v}{v_{0}} - 1$ where $$v_{0}$$ is the rate of the catalysed reaction in the absence of the activator and $$v$$ is the rate of the catalysed reaction in the presence of the activator.
3. When some of the energy required for a reaction to occur is provided by a previous exothermic chemical reaction there is said to be chemical activation.
See: catalysis, chemical activation