Photostationary state

{
  "id": "MLC-T-CHM-008927",
  "term": "Photostationary state",
  "field": "Chemistry",
  "definition": "A steady state reached by an irradiated system, usually a reversible photoreaction such as A to B, in which the interconverting species form and disappear at equal rates, so the composition no longer changes. It differs from thermodynamic equilibrium because continued light absorption maintains it. When both directions are photochemical, the ratio of B to A equals the absorptivity of A times its quantum yield, divided by the same product for B, at the irradiation wavelength, independent of light intensity.",
  "subject": "Organic and Biomolecular Chemistry",
  "references": [
    "PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2265 (https://doi.org/10.1351/pac199668122223)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/photostationary-state/"
}