Kinetic isotope effects in the reaction of fluorine atoms with molecular hydrogen. II. The F + HD/DH intramolecular isotope effect

Abstract

The intramolecular kinetic isotope effect in the reaction of fluorine atoms with HD molecules, F + HD → lim k F + HD HF + D , F + DH → lim k F + DH DF + H , was measured as function of reaction temperature in the range of 159–413 °K. The measured isotope effect can be expressed as an Arrhenius‐type equation: k F+HD/k F+DH = (1.26 ± 0.02) exp[(70 ± 6)/RT]. Experiments were carried out in a fast flow system with direct mass spectrometric analysis of reaction products. The experimental results for k F+HD/k F+DH, as well as results for k F+H2 /k F+D2 which were reported in an earlier publication, are compared with calculations based on transition state theory, using empirical and semiempirical models.