Combination transition

{
  "id": "MLC-T-CHM-002266",
  "term": "Combination transition",
  "field": "Chemistry",
  "definition": "A vibrational transition in which two or more vibrational quantum numbers change together, so that one photon excites several normal modes at once. The resulting combination band lies near the sum of the wavenumbers of the fundamentals involved, lowered slightly by anharmonicity, and is weaker than the fundamental bands. Combination bands appear in infrared, near-infrared and Raman spectra.",
  "subject": "Analytical Chemistry",
  "references": [
    "PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 741 (https://doi.org/10.1515/pac-2019-0203)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/combination-transition/"
}