radiant power, \(P\)

@[email protected] emitted, transferred or received as radiation. SI unit is \(\text{J s}^{-1} = \text{W}\).
  1. Mathematical definition: \(P = \text{d}Q/\text{d}t\). If the @[email protected] \(Q\) is constant over the time interval, \(P = Q/t\).
  2. In @[email protected], flux  (\(\varPhi\)) is used with the same units as \(P\). The symbol \(\varPhi\) is reserved for @[email protected] in @[email protected] Therefore, the use of flux (\(\varPhi\)) is not recommended.
PAC, 2007, 79, 293. (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 410 [Terms] [Paper]