Absorption cross-section

{
  "id": "MLC-T-CHM-000076",
  "term": "Absorption cross-section",
  "field": "Chemistry",
  "definition": "A measure of the probability that a photon will be absorbed by a molecule or atom. It represents the effective area that a particle presents to an incident photon for absorption. The absorption cross-section is typically expressed in units of area, such as square meters (m²) or barns (1 barn = 10⁻²⁸ m²), and is related to the absorption coefficient and the number density of the absorbing species.",
  "subject": "Physical and Biophysical Chemistry",
  "see_also": [
    "Avogadro constant",
    "absorption coefficient"
  ],
  "references": [
    "Green Book, 2nd ed., p. 32 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/absorption-cross-section/"
}