Avoided crossing

{
  "id": "MLC-T-CHM-001031",
  "term": "Avoided crossing",
  "field": "Chemistry",
  "definition": "A phenomenon in quantum mechanics where two electronic potential energy surfaces of the same symmetry approach each other but do not intersect. Instead, they repel each other, leading to a change in the character of the electronic states as the molecular geometry changes. This interaction is described by the non-crossing rule.",
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "intended crossing",
    "surface crossing"
  ],
  "references": [
    "PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2229 (https://doi.org/10.1351/pac199668122223)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/avoided-crossing/"
}