Term: radiation continuum
https://doi.org/10.1351/goldbook.R05052

Definition:
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.

Related Terms:
1) wavelength (http://doi.org/10.1351/goldbook.W06659).
2) band spectra (http://doi.org/10.1351/goldbook.B00595).
3) radiation (http://doi.org/10.1351/goldbook.R05048).

Source: 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)

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. https://doi.org/10.1351/goldbook.R05052

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