aktivatsioonibarjäär

Aktivatsioonibarjäär, often referred to as the activation energy, is a fundamental concept in chemistry and physics describing the minimum amount of energy required to initiate a chemical reaction or to enable a system to transition from a metastable state to a more stable state. For a chemical reaction to occur, reactant molecules must possess sufficient kinetic energy to overcome this energy barrier. This energy is needed to break existing chemical bonds and to form new ones, facilitating the transformation of reactants into products.

The concept of activation energy is closely related to the transition state theory, which posits that reactions proceed through an unstable, high-energy intermediate state called the transition state. The activation energy is the difference in energy between the reactants and this transition state. Factors such as temperature significantly influence the rate of a reaction because a higher temperature means a larger proportion of molecules will have kinetic energy equal to or exceeding the activation energy. Catalysts work by lowering the activation energy, thereby increasing the reaction rate without being consumed in the process. Understanding the activation barrier is crucial for predicting reaction kinetics and designing chemical processes.