Theory of the kinetic isotope effect

The kinetic isotope effect in proton transfer reactions is calculated taking the molecular repulsion potential U(R) into account. The Morse function is used as a model for U(R). Quantitative estimates show that the theory developed yields k.i.e. magnitudes that agree with experiment for reasonable parameter values. The conclusion is drawn that the criticism of our theory by Bell is not sufficiently well-founded because it is based on the simplest model, which does not take into account some important effects. (author)