Illustrated Glossary of Organic Chemistry

Fluorescence: A process in which a substance absorbs photons of one energy and subsequently radiates photons of a lower energy (longer wavelength). Fluorescence is frequently use to detect and quantify molecules in small quantities, such as in thin-layer chromatography (TLC) or high-performance liquid chromatography (HPLC). Some organisms have fluorescent proteins.

Coronene (a polycyclic aromatic hydrocarbon) occurs naturally as yellow crystals in a mineral called carpathite. It appears yellow under white light. However when illuminated with 254 nm ultraviolet light (shortwave ultraviolet), it glows bright white-blue as it radiates visible light photons (~ 400 to ~ 700 nm).


A scorpion fluorescing under a blacklight (longwave ultraviolet light; ~ 350-370 nm).