Annihilation

{
  "id": "MLC-T-CHM-000625",
  "term": "Annihilation",
  "field": "Chemistry",
  "definition": "A process in which a particle and its antiparticle interact and both disappear, their mass being converted into energy, usually as photons. An electron and a positron annihilate into two gamma-ray photons of 511 keV each. In photochemistry the word names the interaction of two excited species, as in energy pooling, which leaves one in an excited state and the other in its ground state.",
  "synonyms": [
    "energy pooling"
  ],
  "subject": "Analytical Chemistry",
  "see_also": [
    "antiparticle",
    "electronic state",
    "spin conservation rule",
    "triplet-triplet annihilation"
  ],
  "references": [
    "Orange Book, 2nd ed., p. 211 (https://media.iupac.org/publications/analytical_compendium/)",
    "PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2228 (https://doi.org/10.1351/pac199668122223)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/annihilation/"
}