08291 IUPAC Gold Book - spectrum 10.1351/goldbook.08291 08291 current synonym: vibrational spectrum 1 Graph of a quantity derived from the radiant power at each wavelength (frequency or wavenumber) as ordinate plotted against the wavelength (frequency or wavenumber) of electromagnetic radiation as abscissa. In mid-infrared and Raman spectroscopy, wavenumber is mostly used today, while it is more commonly replaced by wavelength in near infrared spectroscopy. Quantities plotted include absorbance, absorption coefficient, transmittance, reflectance, luminescence. Raman spectroscopy https://goldbook.iupac.org//terms/view/08669 electromagnetic radiation https://goldbook.iupac.org//terms/view/08242 mid-infrared https://goldbook.iupac.org//terms/view/08617 near infrared spectroscopy https://goldbook.iupac.org//terms/view/08642 wavelength https://goldbook.iupac.org//terms/view/08300 wavenumber https://goldbook.iupac.org//terms/view/08302 PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 675 (https://doi.org/10.1515/pac-2019-0203) https://goldbook.iupac.org/terms/view/08291/html https://goldbook.iupac.org/terms/view/08291/json https://goldbook.iupac.org/terms/view/08291/plain Citation: 'spectrum' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.08291 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-05-30T22:34:44+00:00