vibrational energy
Quick Summary
Molecules possess vibrational energy due to the motion of their atoms. This motion causes the chemical bonds within the molecule to stretch and compress, oscillating around an average length. This vibrational energy is quantized, meaning it can only exist at specific discrete levels, determined by the molecule's vibrational quantum number and the force constant of its chemical bonds.12
For a diatomic molecule, the vibrational energy can be approximated by the formula (E_v = (v + \frac{1}{2})h\nu_0), where (v) is the vibrational quantum number, (h) is Planck's constant, and (\nu_0) is a frequency related to the bond's stiffness. Real molecules, however, exhibit anharmonic oscillations, meaning the energy levels are not perfectly spaced and can allow for transitions involving changes greater than one quantum number.21
Vibrational energy changes can be observed through spectroscopy, such as infrared or Raman spectroscopy. These techniques analyze how molecules interact with light, revealing information about their vibrational states.32
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