fotolüüsi

Fotolüüs, also known as photolysis, is a chemical process where molecules are broken down by photons. This process is fundamental to many natural phenomena and technological applications. In essence, light energy is absorbed by a molecule, causing it to enter an excited state. This excitation can lead to the breaking of chemical bonds within the molecule, resulting in the formation of new, often simpler, substances.

A prime example of photolysis occurs in the Earth's atmosphere. The ozone layer, crucial for absorbing harmful ultraviolet (UV) radiation from the sun, is maintained through a photolytic cycle. UV photons split oxygen molecules (O2) into individual oxygen atoms, which then react with other oxygen molecules to form ozone (O3). Conversely, ozone itself can be broken down by UV light, regenerating oxygen molecules.

Another significant area where photolysis plays a role is in photosynthesis, the process by which plants convert light energy into chemical energy. Chlorophyll pigments absorb light, initiating a series of reactions that split water molecules, releasing electrons and protons necessary for sugar production. This water splitting is a direct instance of photolysis.

Beyond natural processes, photolysis is utilized in various industrial and scientific fields. It is employed in water purification systems to break down contaminants using UV light. In analytical chemistry, photolytic methods can be used to generate reactive species for study or to initiate specific chemical reactions. The understanding and application of photolysis continue to be important in chemistry and related disciplines.