photon fluence, $H p , o$ , $F p , o$

Amount of photons (quanta of radiation) incident on a small sphere from all directions, divided by the cross-sectional area of that sphere and integrated over time. Photons per surface area ( $quanta m −2$ ). SI unit is $m −2$ .

Notes:

Mathematical definition: $H p , o = F p , o = d N p / d S = ∫ t E p , o ⁢ d t$ with $E p , o$ the photon fluence rate, integrated over the duration of the irradiation, $t$ . If $E p , o$ is constant over the time interval, $H p , o = F p , o = E p , o t$
This quantity can be used on a chemical amount basis by dividing $H p , o$ by the Avogadro constant, the symbol then being $H n , p , o$ , the name 'photon fluence, amount basis', SI unit is $mol m −2$ ; common unit is $einstein m −2$ .

Source:

PAC, 2007, 79, 293 (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 395

Related index:

IUPAC > Gold Book > math/physics > quantities

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Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook.

Last update: 2014-02-24; version: 2.3.3.

DOI of this term: https://doi.org/10.1351/goldbook.P04634.

Original PDF version: http://www.iupac.org/goldbook/P04634.pdf. The PDF version is out of date and is provided for reference purposes only. For some entries, the PDF version may be unavailable.

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photon fluence, $H p , o$ , $F p , o$