infrared 

https://doi.org/10.1351/goldbook.IT07399
Region of the electromagnetic spectrum extending from 780 nm to about 20000 nm.
According to the CIE, the range between 780 nm and 1 mm is subdivided into:
IR-A 780–1400 nm
IR-B 1.4–3 μm
IR-C 3 μm–1 mm
Note:
This is the wavelength region in which absorption by a molecular entity causes excitation of its vibrational, rotational, and bending modes.
Sources:
PAC, 2007, 79, 293. (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 354 [Terms] [Paper]
International Lighting Vocabulary, International Commission on Illumination (CIE), Geneva, Switzerland (1987). [Terms] [Source]
Citation: 'infrared' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.IT07399 RIS BibTex EndNote
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Last revised: February 24, 2014