Energy transfer by complex formation

In fluid solutions the rate coefficient feQM of the process M + Q- M + Q ftQM 

The experimental results fit the Stern—Volmer equation in most cases of energy transfer reactions studied with polymer solutions. Lpkac et al. [61] have used the Stern—Volmer equation to interpret their results concerning the photolysis of polyphenylvinylketone in solution in the presence of quenchers of the excited triplet state of the aromatic ketone chromophore (Fig. 38). The slopes of the straight lines obtained allow the efficiency of various acceptors to be compared. On this basis, the authors have shown that naphthalene is about twenty times more efficient as a triplet quencher when introduced into the polymer chain as vinyl-naphthalene rather than as an additive in the solution. Such a result is not unexpected since the actual concentration of the acceptor inside the polymer coil is much higher than the mean quencher concentration when naphthalene is used as an additive. The process is usually diffusion 

The Stern—Volmer and Perrin equations, (v) and (vi), both allow a quantitative characterization of the efficiency of non-radiative energy transfers. They are useful for the comparison of various donoi -acceptor systems, although they provide no information concerning the nature of the excited state involved and the mechanism of the energy transfer process. More appropriate theories have been established to describe non-radiative energy transfers that occur when there is close resonance between the initial and final states. 

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