Fotódisszociáció

Fotódisszociáció, also known as photodissociation or photolysis, is a chemical process where a molecule breaks apart into two or more pieces as a result of absorbing one or more photons of light. This absorption event typically occurs in the ultraviolet or visible spectrum. The energy of the absorbed photon excites the molecule to a higher energy state, making the bonds within the molecule weaker and more prone to breaking.

The specific wavelength of light required for photolysis depends on the molecule's structure and the strength of its chemical bonds. Molecules with weaker bonds or those that absorb light at specific wavelengths are more susceptible to this process. For instance, ozone (O3) in the Earth's stratosphere undergoes photodissociation when it absorbs ultraviolet radiation, breaking down into an oxygen molecule (O2) and a single oxygen atom (O). This is a crucial step in the formation and destruction of the ozone layer.

Photodissociation plays a significant role in various natural phenomena and industrial applications. In atmospheric chemistry, it contributes to the formation and degradation of pollutants and greenhouse gases. In biology, it is essential for processes like vision, where light absorption by retinal molecules triggers a cascade of events leading to nerve impulses. In technology, photodissociation is utilized in photolithography for manufacturing microelectronic devices and in certain types of sterilization techniques. Understanding photolysis is key to comprehending many chemical reactions occurring in diverse environments.