Photon fluence rate

Term · Chemistry · MLC-T-CHM-008900

The number of photons entering a small sphere from all directions in unit time, divided by the sphere's cross-sectional area, so its SI unit is photons per square metre per second. It is the time derivative of the photon fluence and, like it, counts every direction equally. Dividing by the Avogadro constant gives the same quantity in mol m⁻² s⁻¹, or einstein per square metre per second.

Table 1. Record
Identifier	MLC-T-CHM-008900
Field	Chemistry
Subject	Organic and Biomolecular Chemistry
References	PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 395 (https://doi.org/10.1351/pac200779030293)
See also	Avogadro constant; Angle; Fluence rate; Photon irradiance; Photon radiance

Record as JSON

{
  "id": "MLC-T-CHM-008900",
  "term": "Photon fluence rate",
  "field": "Chemistry",
  "definition": "The number of photons entering a small sphere from all directions in unit time, divided by the sphere's cross-sectional area, so its SI unit is photons per square metre per second. It is the time derivative of the photon fluence and, like it, counts every direction equally. Dividing by the Avogadro constant gives the same quantity in mol m⁻² s⁻¹, or einstein per square metre per second.",
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "Avogadro constant",
    "angle",
    "fluence rate",
    "photon irradiance",
    "photon radiance"
  ],
  "references": [
    "PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 395 (https://doi.org/10.1351/pac200779030293)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/photon-fluence-rate/"
}

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