Effects of Different Isotopes

The present section would not be complete without a discussion of the 

The line width which should be experimentally observed for the two isotopes may be calculated from Eq. (5.31). Let us define 

When n 1 the above ratio is always unity. For n - 1 the ratio becomes a function of n. Eq. (5.42), although written in a different way, was originally derived by Hertz [40] who was the first to point out the usefulness of studying the different halogen isotopes in studies of exchange rates. Judging from the sparse use of this technique in later publications his pleas were largely unnoticed, however. 

Here the variation has been calculated not only from Eq. (5.42) 

We may note that at small values of, i,e, slow exchange 

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We will use reaction 10.15 to illustrate two important concepts of kinetic isotope effect studies. The first concerns the relation between isotope effects of different isotopes of the same element, say D and T. We denote the rate constant of reaction 10.15 by kn and consider isotope effects when one hydrogen in the a-position is substituted by deuterium or tritium ... 

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