05052 IUPAC Gold Book - radiation continuum 10.1351/goldbook.R05052 R05052 current 1 Continuous (in the wavelength, not time sense) radiation arising for example from non-quantized free-free transitions of electrons in the fields of the ions, free-bound transitions or radiative recombinations of electrons and ions, incandescent radiation emitted by hot solids (when the radiation distribution conforms to that described by Planck's law, it is considered black-body radiation) and unresolvable band spectra, i.e. where the spectral lines are wider than the spacings between them. band spectra https://goldbook.iupac.org/terms/view/B00595 radiation https://goldbook.iupac.org/terms/view/R05048 wavelength https://goldbook.iupac.org/terms/view/W06659 PAC, 1985, 57, 1453. 'Nomenclature, symbols, units and their usage in spectrochemical analysis - V: Radiation sources (Recommendations 1985)' on page 1462 (https://doi.org/10.1351/pac198557101453) https://goldbook.iupac.org/terms/view/R05052/html https://goldbook.iupac.org/terms/view/R05052/json https://goldbook.iupac.org/terms/view/R05052/plain Citation: 'radiation continuum' 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.R05052 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. 2026-07-27T02:05:16+00:00