Potential coupling

{
  "id": "MLC-T-CHM-009315",
  "term": "Potential coupling",
  "field": "Chemistry",
  "definition": "Interaction between different vibrational motions of a molecule that arises because the potential energy function contains terms linking their displacements. Cross terms of second order in the displacements give harmonic potential coupling, the mixing that produces normal modes, whereas terms of third order and above give anharmonic potential coupling. Anharmonicity of this kind produces overtones and combination bands, as well as shifts through Fermi resonance, in infrared and Raman spectra.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "mechanical anharmonicity",
    "mechanical harmonicity",
    "vibrational potential energy"
  ],
  "references": [
    "PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 760 (https://doi.org/10.1515/pac-2019-0203)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/potential-coupling/"
}