anharmonic motion

physics

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June 18, 2026

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Anharmonic motion is a deviation from simple harmonic motion (SHM) in physics. In SHM, the restoring force is directly proportional to the displacement from equilibrium, resulting in repetitive, symmetrical oscillations with a constant period.12

However, in anharmonic motion, this direct proportionality does not hold. This can occur in systems with more complex restoring forces or when oscillations become large. As a result, anharmonic motion is not perfectly symmetrical, and its period may depend on the amplitude of the oscillation. While SHM is a fundamental concept for understanding many physical phenomena, including timekeeping and wave motion, anharmonic motion describes more complex and realistic oscillatory behaviors found in various systems.3421

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spectroscopy
Energy states of real diatomic molecules
…real molecules the oscillations are anharmonic. The potential for the oscillation of a molecule is the electronic energy plotted as a function of internuclear separation (Figure 7A). Because this curve is nonparabolic, the oscillations are anharmonic and the energy levels are perturbed. This results in a decreasing energy level separation…
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…real molecules the oscillations are anharmonic. The potential for the oscillation of a molecule is the electronic energy plotted as a function of internuclear separation (Figure 7A). Because this curve is nonparabolic, the oscillations are anharmonic and the energy levels are perturbed. This results in a decreasing energy level separation…
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sound
In nonharmonic systems
The resonant systems described above have a series of standing-wave resonances that vibrate at the frequencies of the overtone series, but there are several systems whose resonances are not so simply related.
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The resonant systems described above have a series of standing-wave resonances that vibrate at the frequencies of the overtone series, but there are several systems whose resonances are not so simply related.
Read More