Transfer of excitation energy by radiative deactivation of a donor molecular entity and reabsorption of the emitted radiation by an acceptor molecular entity.
Notes: - Radiative transfer results in a decrease of the donor @F02453@ intensity in the region of @S05818@. Such a distortion of the @F02453@ spectrum is called inner-@F02384@ effect.
- Radiative energy transfer depends on the shape and size of the vessel utilized and on the configuration of the latter with respect to excitation and observation.
- The fraction a of photons emitted by D and absorbed by A is given by \[a = \frac{1}{\mathit{\Phi}_{\text{D}}^{0}}\int _{_{\lambda }}I_{\lambda}^{\text{D}}(\lambda)\left [ 1 - 10^{-\varepsilon_{\text{A}}(\lambda)c_{\text{A}}\, l} \right ]\text{d}\lambda\] where cA is the molar concentration of acceptor, ΦD0 is the @F02453@ @Q04991@ in the absence of acceptor, l is the thickness of the sample, IλD(λ) and ɛA(λ) are the @S05813@ of the @S05827@ of the donor @F02453@ and the @M03972@ of the acceptor, respectively, with the @NT07086@ condition ΦD0 = ∫(λ).IλD(λ).dλ.
For relatively low @A00028@, a can be approximated by \[a = \frac{2.3}{\mathit{\Phi}_{\text{D}}^{0}}c_{\text{A}}\, l\int _{\lambda}I_{\lambda}^{\text{D}}(\lambda)\varepsilon_{\text{A}}(\lambda)\text{d}\lambda\] where the integral represents the overlap between the donor @F02453@ spectrum and the acceptor @A00043@.
Source:
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 411 (https://doi.org/10.1351/pac200779030293)