Conical intersection

{
  "id": "MLC-T-CHM-002435",
  "term": "Conical intersection",
  "field": "Chemistry",
  "definition": "A point in the coordinate space of a polyatomic molecule where two or more potential energy surfaces of the same spatial and spin symmetry become degenerate. This intersection of electronic states provides a pathway for extremely fast, non-radiative transitions between them, occurring on a femtosecond timescale. The geometry around the point of degeneracy forms a double cone shape, giving the feature its name.",
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "branching plane",
    "channel",
    "degeneracy",
    "excited state",
    "ground state",
    "intersection space",
    "multiplicity",
    "photochemical reaction",
    "potential-energy surface",
    "radiationless deactivation",
    "singlet state",
    "triplet state"
  ],
  "references": [
    "PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 317 (https://doi.org/10.1351/pac200779030293)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/conical-intersection/"
}