normal mode

of vibration
synonyms: normal mode, normal vibration, normal vibration mode
https://doi.org/10.1351/goldbook.08648
One of the \(3N - 6\) (\(3N - 5\) for a linear molecule) modes of vibration that would add to give the total vibrational motion in a molecule if the interatomic potential were strictly quadratic in the displacements from equilibrium.
Note: Normal modes of vibration is an idealized concept that has proved extremely useful in analysing spectra in vibrational spectroscopy.
Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 757 [Terms] [Paper]
Citation: 'normal mode' 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.08648 RIS BibTex EndNote
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