Applications of kinetic analysis to photoreactions

Different approaches are given in Chapters 2 and 3 for the calculation of the relationship between the concentrations of the reactants and the reaction time, assuming mechanism and kinetic constants are known. Such rate equations can be formed for any complex mechanism, at least in principle, since there is a well defined route from mechanism to concentration and time laws. 

The aim of any kinetic analysis is to determine the mechanism using concentration-time measurements. Therefore a variety of different methods have been described in Chapter 4 to obtain these data. A kinetic analysis has turned out to be successful if the coefficient scheme according to Example 2.1 and explained in Section 2.1.1.1 together with the numerical values of the rate constants are determined for the reaction under examination. 

In general many mechanisms can result in the same functional relationship between concentration and time. For this reason the mechanism determined and in consequence the rate constants obtained are not all unambiguous. Furthermore accuracy and reproducibility of the measurements are limited. They vary with the method used for the determination of the concentrations with time. Thus the limitation in the measured signals and the variety of rate laws increase the many mechanisms fitting to the signals measured. For this reason the only positive result of any kinetic analysis can be in principle  

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