Title: Bloch–Siegert shift
Long Title: IUPAC Gold Book - Bloch–Siegert shift
DOI: 10.1351/goldbook.08315
Status: current

Definition
Frequency difference seen for a nuclear magnetic resonance signal when a radiofrequency field is applied during the acquisition time.

Note
The shift arises from the effective magnetic field generated by the applied RF field. The resonances are always moved away from the frequency of the irradiating field and are inversely proportional to the difference in frequency between the irradiation and the resonance.

Related Terms
- acquisition time: https://goldbook.iupac.org//terms/view/08312
- nuclear magnetic resonance: https://goldbook.iupac.org//terms/view/08218
- radiofrequency: https://goldbook.iupac.org//terms/view/08279

Source
- PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 682 (https://doi.org/10.1515/pac-2019-0203)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/08315/html
- json: https://goldbook.iupac.org/terms/view/08315/json
- xml: https://goldbook.iupac.org/terms/view/08315/xml

Citation: Citation: 'Bloch–Siegert shift' 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.08315
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Accessed: 2026-06-29T10:31:36+00:00