Irreversible quenching, high-concentration

Both of these equations can be universally expressed through the Stern-Volmer constant k. The latter one has been used already in Section XII.B as a standard for comparison between the different theories of irreversible quenching. In the case of the reversible reaction (3.703), the problem is more difficult, especially at high concentrations of B molecules. After the dissociation, other B molecules can be involved in the reaction with A. This many-particle competition for the partner couples the motion of the molecules, making the problem unsolvable analytically. Thus only approximate solutions were obtained by means of different methods and assumptions whose validity very often remains unclear. 

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