Photon irradiance, Ep, integrated over the time of irradiation for a beam incident
from all upward
directions. SI unit is m-2.
- Mathematical definition: Hp = ∫(t) Ep.dt. If the @P04637-2@ is constant over the time interval, Hp = Ep.t.
- This term refers to a beam not scattered or reflected by the target or its surroundings. For a beam incident from all directions photon fluence (Hp,o, Fp,o) is an equivalent term.
- This quantity can be used on a @C01019@ basis by dividing Hp by the @A00543@, the symbol then being Hn,p, the name 'photon exposure, amount basis', SI unit is mol m-2; common unit is einstein m-2.
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 394 (https://doi.org/10.1351/pac200779030293)