photon exitance, Mp

Also contains definition of: specific photon emission
Synonym: photon emittance
https://doi.org/10.1351/goldbook.P04631
Photon flux, number basis, qp, emitted by an element of the surface containing the source point under consideration divided by the area S of that element. SI unit is s-1 m-2.
Notes:
  1. Mathematical definition: dq(p)/dS. If qp is constant over the surface area considered, Mp = qp/S.
  2. Formerly called photon emittance.
  3. This quantity can be expressed on a @C01019@ basis by dividing Mp by the @A00543@. In this case the symbol is Mn,p, the name 'photon @E02264@, amount basis', SI unit is mol s-1 m-2; common unit is einstein s-1 m-2.
Source:
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 394 (https://doi.org/10.1351/pac200779030293)