Sum transition

{
  "id": "MLC-T-CHM-011579",
  "term": "Sum transition",
  "field": "Chemistry",
  "definition": "A spectroscopic transition that occurs when a molecule simultaneously absorbs energy corresponding to the sum of two or more fundamental vibrational or rotational modes. This results in an absorption band at a frequency equal to the sum of the frequencies of the individual transitions. Such transitions are typically weaker than fundamental transitions and are observed in infrared and Raman spectroscopy.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "combination transition"
  ],
  "references": [
    "PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 764 (https://doi.org/10.1515/pac-2019-0203)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/sum-transition/"
}