Quantum yield

The quantum yield of a radiation-induced process is the number of times that a defined event occurs per photon absorbed by the system. The "event" may represent a chemical reaction, for example the decomposition of a reactant molecule:

$\Phi = \frac{\rm \#\ molecules \ decomposed} {\rm \#\ photons \ absorbed}$

Quantum Yield can also be defined for other events, such as fluorescence (emission of photons) in which case the quantum yield is defined by the equation:

$\Phi = \frac {\rm \#\ photons \ emitted} {\rm \#\ photons \ absorbed}$

Here, quantum yield is essentially the emission efficiency of a given fluorophore in this case.

Example

Quantum yield is used in modeling photosynthesis (Skillman 2008):

$\Phi = \frac {\rm \mu mol\ CO_2 \ fixed} {\rm \mu mol\ photons \ absorbed}$

See also

• Quantum Efficiency

References

Skillman, J.B. 2008. Quantum yield variation across the three pathways of photosynthesis: not yet out of the dark. Journal of Experimental Botany, 59(7):1647–1661 doi:10.1093/jxb/ern029