Term: absorptivity [obsolete]
https://doi.org/10.1351/goldbook.A00044

Definition:
absorptance divided by the optical path length. For very low attenuance it approximates the absorption coefficient [within the approximation (1 - e-A) ~ A]. The use of this term is not recommended.

Related Terms:
1) absorptance (http://doi.org/10.1351/goldbook.A00035).
2) absorption coefficient (http://doi.org/10.1351/goldbook.A00037).
3) attenuance (http://doi.org/10.1351/goldbook.A00513).

Source: PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2227 (https://doi.org/10.1351/pac199668122223)

Citation: 'absorptivity <span class='text-danger'>[obsolete]</span>' 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.A00044

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