absorbed (spectral) photon flux density in in situ microanalysis

https://dx.doi.org/10.1351/goldbook.AT07312
Number of photons of a particular wavelength per time interval (spectral photon flux, number basis, q p , λ, or spectral photon flux, amount basis, q n , p , λ) absorbed by a system per volume, V. On number basis, SI unit is s −1 m −4 common unit is s −1 cm −3 nm −1 On amount basis, SI unit is mol s −1 m −4 common unit is einstein s −1 cm −3 nm −1.
Notes:
  1. Mathematical expression: q p , λ 0 1 − 10 − A λ V on number basis, q n , p , λ 0 1 − 10 − A λ V on amount basis, where A λ is the absorbance at wavelengthλ and superscript 0 (zero) indicates incident photons.
  2. Absorbed spectral photon flux density (number basis or amount basis) should be used in the denominator when calculating a differential quantum yield and using in the numerator the rate of change of the number concentration, d C d t or the rate of change of the amount concentration, d c d t, respectively.
Source:
PAC, 2007, 79, 293 (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 297