Term: Rydberg transition
https://doi.org/10.1351/goldbook.R05432

Definition:
An electronic transition described approximately as promotion of an electron from a 'bonding' orbital to a Rydberg orbital. Spectral bands corresponding to Rydberg transitions approximately fit the Rydberg formula: \[\sigma = I - \frac{R}{(n\,-\,\mathit{\Delta })^{2}}\] where σ is the wavenumber, I the ionization potential of the atom or molecular entity, n a principal quantum number, R the Rydberg constant, and Δ the quantum defect which differentiates between s, p, d, etc., orbitals. The notation used is, e.g. π → ns.

Related Terms:
1) promotion (http://doi.org/10.1351/goldbook.P04877).
2) ionization potential (http://doi.org/10.1351/goldbook.I03208).
3) rydberg constant (http://doi.org/10.1351/goldbook.R05430).
4) rydberg orbital (http://doi.org/10.1351/goldbook.R05431).

Source: PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2272 (https://doi.org/10.1351/pac199668122223)

Citation: 'Rydberg transition' 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.R05432

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