Term: Lambert law
https://doi.org/10.1351/goldbook.L03445

Definition:
The fraction of light absorbed by a system is independent of the incident radiant power (P λ 0). This law holds only if P λ 0 is small, scattering is negligible, and multiphoton processes, excited state populations, and photochemical reactions are negligible.

Related Terms:
1) radiant power (http://doi.org/10.1351/goldbook.R05046).
2) scattering (http://doi.org/10.1351/goldbook.S05487).
3) excited state (http://doi.org/10.1351/goldbook.E02257).
4) absorbance (http://doi.org/10.1351/goldbook.A00028).
5) beer–lambert law (http://doi.org/10.1351/goldbook.B00626).

Source: PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2251 (https://doi.org/10.1351/pac199668122223)

Citation: 'Lambert law' 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.L03445

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