Term: Rydberg state
https://doi.org/10.1351/goldbook.RT07096

Definition:
An electronic state that arises by the excitation of a valence electron to a diffuse atomic-like orbital. For instance, the lowest lying Rydberg state (n, 3S) of NH3 can be described as resulting from the excitation of a non-bonding orbital to a 3S Rydberg orbital.

Related Terms:
1) electronic state (http://doi.org/10.1351/goldbook.ET07026).
2) valence (http://doi.org/10.1351/goldbook.V06588).
3) rydberg orbital (http://doi.org/10.1351/goldbook.R05431).

Source: PAC, 1999, 71, 1919. 'Glossary of terms used in theoretical organic chemistry' on page 1961 (https://doi.org/10.1351/pac199971101919)

Citation: 'Rydberg state' 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.RT07096

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