Non-Arrhenius rate constants in complex reaction systems

Explicit analytical expressions for the rate constants have been derived which take into account the distortion of the Maxwellian caused by chemical reactions. In contrast to simple systems involving a single chemical reaction, where the rate constant is usually not affected much by the distortion, the analytical expressions show how in complex reaction systems the frequency factors of the rate constants for the reactions with the higher threshold energies may be substantially less than the Arrhenius values. The validity of the analytical expressions is verified by comparison with exact numerical solutions.