Generally used to describe a chemical reaction caused by absorption of ultraviolet, visible or infrared radiation. There are many ground-state reactions, which have photochemical counterparts. Among these are photochemical nitrogen extrusions, photocycloadditions, photodecarbonylations, photodecarboxylations, photoenolizations, photo-Fries rearrangement, photoisomerizations, photooxidations, photorearrangements, photoreductions, photosubstitutions, etc.
Note:
Photochemical paths offer the advantage over thermal methods of forming thermodynamically disfavoured products, overcome large @A00093@ barriers in a short period of time, and allow reactivity otherwise inaccessible by thermal methods.
Source:
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 386 (https://doi.org/10.1351/pac200779030293)