Variational transition state theory calculations of the reaction rates of F with H2, D2, and HD and the intermolecular and intramolecular kinetic isotope effects

TLDR: In this paper, the authors used variational transition state theory to calculate rate constants and kinetic isotope effects for the reactions F+H2→HF+H (with rate constant k1), F+D2→DF+D(k2), and two other isotopic analogs as functions of temperature.

Abstract: We use variational transition state theory to calculate rate constants and kinetic isotope effects for the reactions F+H2→HF+H (with rate constant k1), F+D2→DF+D(k2), and two other isotopic analogs as functions of temperature. The calculations are performed using a recently proposed partly empirical, partly ab initio potential energy surface, called surface No. 5, and also using a new surface, called surface No. 5A, introduced here to test the effect of a higher classical saddle point on the reaction rates, kinetic isotope effects, and reaction thresholds. The various theoretical results are compared to the available experiments to test the validity of these potential energy surfaces. For those rate constants and kinetic isotope effects for which there is more than one experimental value at a given temperature, the theoretical results for reactions on surface No. 5 agree with experiment about as well as the individual experiments agree with each other. At T>373 K where there is only one experimental measu...