Electromagnetic radiation of
wavelength between approximately
\(\pu{780 nm}\) and
\(\pu{1000 \upmu\!m}\) or of
wavenumber between approximately
\(\pu{13000 cm-1}\) and
\(\pu{10 cm-1}\).
Notes: - The infrared range is sub-divided into three regions: near-infrared: \(\pu{780 nm}\) to \(\pu{2.5 \upmu\!m}\) (\(\pu{12800 cm-1}\) to \(\pu{400 cm-1}\)); mid-infrared: \(\pu{2.5 \upmu\!m}\) to \(\pu{25 \upmu\!m}\) (\(\pu{4000 cm-1}\) to \(\pu{400 cm-1}\)) and far infrared: \(\pu{25 \upmu\!m}\) to \(\pu{1000 \upmu\!m}\) (\(\pu{400 cm-1}\) to \(\pu{10 cm-1}\)).
- The wavelength regions given are commonly used in chemistry and relate to working ranges of infrared spectrometers. Note that in other disciplines (e.g., astronomy) the terms are defined for different ranges.
- If there is no ambiguity the term 'infrared' is used for the mid-infrared region.
See: infrared spectroscopy, Raman spectroscopy
Source:
PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 750 (https://doi.org/10.1515/pac-2019-0203)