For a chemical reaction to occur, the reactions need to resolve obstacles for activation. The activation barrier is the sum of the energy needed to get the reaction going. An activation barrier is often considered canonically because during the reaction the molecule must climb over a hill. Since chemical reactions generically exhibit energetic barriers, they will generically possess barrier-type resonances.
Activation energy & Effective collision between reactant molecules are the two barriers for a chemical reaction to occur.
- Activation energy – In chemistry, activation energy is the minimum amount of energy required to activate atoms or molecules to a condition in which they can undergo a chemical or physical transformation.
- Effective collision – Effective collisions are those that result in a chemical reaction, which results in product formation due to an increase in the rate of a chemical reaction that occurs when the two reactant molecules are correctly orientated and have attained the threshold value at the time of the collision. In order to produce an effective collision, reactant particles must possess some minimum amount of energy.