rotational branch

https://doi.org/10.1351/goldbook.08675
Spectral lines in the rotation-vibration spectrum of a gas that derive from the same change in rotation quantum number, J.
Notes:
  1. ΔJ=Jupper−Jlower=−2,−1,0,+1 and +2 for the O, P, Q, R and S branches, respectively.
  2. The most commonly observed branches for simple molecules are the P, Q and R branches in infrared spectroscopy and the O, Q and S branches in Raman spectroscopy.
Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 762 [Terms] [Paper]
Citation: 'rotational branch' 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.08675 RIS BibTex EndNote
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