Mechanical anharmonicity

{
  "id": "MLC-T-CHM-007107",
  "term": "Mechanical anharmonicity",
  "field": "Chemistry",
  "definition": "The deviation of a molecular vibrational potential energy surface from a perfectly parabolic shape, which would correspond to simple harmonic motion. This anharmonicity leads to vibrational energy levels that are not equally spaced and allows for vibrational transitions with changes in quantum number greater than one. It is a fundamental property influencing infrared and Raman spectra.",
  "synonyms": [
    "anharmonicity"
  ],
  "subject": "Analytical Chemistry",
  "see_also": [
    "electrical anharmonicity",
    "vibrational potential energy"
  ],
  "references": [
    "PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 754 (https://doi.org/10.1515/pac-2019-0203)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/mechanical-anharmonicity/"
}