Title: unactivated adsorption process
Long Title: IUPAC Gold Book - unactivated adsorption process
DOI: 10.1351/goldbook.U06552
Status: current

Definition
If the temperature coefficient of the rate of adsorption is very small, the adsorption process is said to be unactivated (i.e. to have a negligible activation energy). In this case the sticking coefficient at low coverages may be near unity particularly for smaller molecules.

Related Terms
- activation energy: https://goldbook.iupac.org//terms/view/A00102
- adsorption: https://goldbook.iupac.org//terms/view/A00155
- coefficient: https://goldbook.iupac.org//terms/view/C01124
- sticking coefficient: https://goldbook.iupac.org//terms/view/S06012

Source
- PAC, 1976, 46, 71. 'Manual of Symbols and Terminology for Physicochemical Quantities and Units - Appendix II. Definitions, Terminology and Symbols in Colloid and Surface Chemistry. Part II: Heterogeneous Catalysis' on page 79 (https://doi.org/10.1351/pac197646010071)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/U06552/html
- json: https://goldbook.iupac.org/terms/view/U06552/json
- xml: https://goldbook.iupac.org/terms/view/U06552/xml

Citation: Citation: 'unactivated adsorption process' 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.U06552
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Accessed: 2026-04-19T00:55:49+00:00