Illustrated Glossary of Organic Chemistry

Ultraviolet spectroscopy (UV): Spectroscopy using photons in the 400-100 nm range. Photons in this energy range cause electronic excitation, so ultraviolet spectroscopy is particularly useful to study aromatic, conjugated, and other substances containing a pi bond. Modern ultraviolet spectrophotometers also cover the visible light range (700-400 nm), in which case the technique is called ultraviolet-visible spectroscopy (UV-vis). Ultraviolet and ultraviolet-visible spectrometry is useful to detect and quantify the presence of substances that absorb UV and/or visible light.