photon fluence rate, \(E_{\text{p,o}}\)
Rate of photon fluence. Total number of photons (\(N_{\text{p}}\)) incident from all directions on a small sphere divided by the cross-sectional area of the sphere and per time interval. SI unit is \(\text{m}^{-2}\ \text{s}^{-1}\). Same as photon @[email protected]
  1. Mathematical definition: \(E_{\text{p,o}} = \text{d}N_{\text{p}}/\left ( \text{d}t\, \text{d}S \right ) = \text{d}H_{\text{p,o}}/\text{d}t\). If \(E_{\text{p,o}}\) is constant over the time interval and the surface, \(E_{\text{p,o}} = N_{\text{p}}/t\, S\). Equivalent definition: \(E_{\text{p,o}} = \int _{4\pi}L_{\text{p}}\text{d}\varOmega\) with \(L_{\text{p}}\) the @[email protected] and \(\varOmega\) the solid @[email protected] of the beams passing through the given point on the surface.
  2. It reduces to @[email protected] \(E_{\text{p}}\) for a parallel and normally incident beam not scattered or reflected by the target or its surroundings.
  3. This quantity can be used on a @[email protected] basis by dividing \(E_{\text{p,o}}\) by the @[email protected], the symbol then being \(E_{n\text{,p,o}}\), the name 'photon @[email protected], amount basis', SI unit is \(\text{mol m}^{-2}\ \text{s}^{-1}\); common unit is \(\text{einstein m}^{-2}\ \text{s}^{-1}\).
PAC, 2007, 79, 293. (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 395 [Terms] [Paper]