Laplace Transformation and Scavenging

Rzad et al. (1970) obtained the relative lifetime distribution of electron-ion recombination in cyclohexane by 1LT of Eq. (7.26). Denoting the probability that the lifetime would be between t and t + dt as f(t) dt, the thusly defined scavenging function at scavenger concentration c% is given by 

To evaluate the absolute kinetics of recombination from Eq. (7.27), it is necessary to obtain a reliable value of fes in addition to a measured from scavenging experiments. For electron scavenging in cyclohexane by biphenyl, Rzad et al. (1970) used fes = 3.0 x 10u M s-1 on the basis of the a value of scavenging 

Chapter 7 Spur Theory of Radiation Chemical Yields 

Rzad et al.( 1970) compared the consequences of the lifetime distribution obtained by ILT method (Eq. 7.27) with the experiment of Thomas et al. (1968) for the decay of biphenylide ion (10-800 ns) after a 10-ns pulse-irradiation of 0.1 M biphenyl solution of cyclohexane. It was necessary to correct for the finite pulse width also, a factor rwas introduced to account for the increase of lifetime on converting the electron to a negative ion. Taking r = 17 and Gfi = 0.12 in consistence with free-ion yield measurement, they obtained rather good agreement between calculated and experimental results. The agreement actually depends on A /r, rather than separately on A or r. 

The discussion so far has been empirical in the sense that Laplace transform method has been utilized in conjunction with an experimentally determined scavenging function without a theoretical model for the recombination kinetics. A theoretical model will be attempted in the following subsections. 

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