Unified theory recombination

The theory of geminate recombination experienced a similar evolution from primitive exponential model and contact approximation [19,20], to distant recombination carried out by backward electron transfer [21], However, all these theories have an arbitrary parameter initial separation of reactants in a pair, / o. This uncertainty was eliminated by unified theory (UT) proposed in two articles published almost simultaneously [22,23], UT considers jointly the forward bimolecular electron transfer and subsequent geminate recombination of charged products carried out by backward electron or proton transfer. The forward transfer creates the initial condition for the backward one. This is the distribution of initial separations in the geminate ion pair/(ro), closely analyzed theoretically [24,25] and inspected experimentally [26,27], It was used to specify the geminate recombination kinetics accompanied by spin conversion and exciplex formation [28-31], These and other applications of UT have been covered in a review published in 2000 [32],... 

Equations (3.420)-(3.421) constitute the formal basis of the extended unified theory, which accounts for the nonlinear effects resulting from the bimolecular production and recombination of ions. Only one step remains to be taken to go from UT to its simplified, Markovian version, which describes the asymptotic relaxation of the system long after the pulse. Using the Green function of Eq. (3.419), one can represent the space integral of its solution in the following form ... 

Figure 3.100. The kinetics of charge accumulation without bulk recombination (dashed lines) and taking into account the bulk recombination (solid lines) calculated with the unified theory (UT) and its Markovian version (M). (a) fast ionization (to = 10 ns) (h) slow ionization (tp = 106ns) at No = 0.01 M, D = D = 10-6 cm2/s, rc = 0. (From Ref. 275.)...

---