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Photochemical immersion well reactor (50 mL) with a mercury-vapor lamp.. Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible (400–750 nm), or infrared radiation (750–2500 nm).
Photodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by absorption of light or photons. It is defined as the interaction of one or more photons with one target molecule that dissociates into two fragments. [1]
PAN is produced in the atmosphere via photochemical oxidation of hydrocarbons to peroxyacetic acid radicals, which react reversibly with nitrogen dioxide (NO 2) to form PAN. [4]: 2680 Night-time reaction of acetaldehyde with nitrogen trioxide is another possible source. [4] Since there are no direct emissions, it is a secondary pollutant.
In chemical terms, actinism is the property of radiation that lets it be absorbed by a molecule and cause a photochemical reaction as a result. Albert Einstein was the first to correctly theorize that each photon would be able to cause only one molecular reaction. This distinction separates photochemical reactions from exothermic reduction ...
Photochemical reactions are initiated by the absorption of a photon, typically in the wavelength range 290–700 nm (at the surface of the Earth). The energy of an absorbed photon is transferred to electrons in the molecule and briefly changes their configuration (i.e., promotes the molecule from a ground state to an excited state). The excited ...
Photosynthetic water splitting (or oxygen evolution) is one of the most important reactions on the planet, since it is the source of nearly all the atmosphere's oxygen. Moreover, artificial photosynthetic water-splitting may contribute to the effective use of sunlight as an alternative energy-source.
The excited photosensitizer then reacts with a ground state, triplet oxygen molecule. This excites the oxygen molecule into the singlet state, making it a reactive oxygen species. Upon excitation, the singlet oxygen molecule reacts with a substrate to form a product. Type II photosensitized reaction result in the photosensitizer being quenched ...
The second reaction is irreversible, and therefore the entire process is irreversible, so triphenylsulfonium triflate is a photoacid generator. The ultimate products are thus a neutral organic sulfide and the strong acid triflic acid. [(C 6 H 5) 3 S +][CF 3 SO − 3] + hν → [(C 6 H 5) 2 S +.][CF 3 SO − 3] + C 6 H. 5 [(C 6 H 5) 2 S +.][CF 3 ...