Reductionist approach to chemical rate constants using conditional energy probabilities

International audienceDifferent rate theories have yielded similar forms of rate constants consistent with the phenomenological Arrhenius law, although they have been derived from various branches of physics including classical thermodynamics, statistical mechanics and quantum mechanics. This convergence supports the validity of the Arrhenius law but also suggests the existence of an even simpler underlying principle. A reductionist approach is proposed here in which the energetic exponential factor is a conditional probability of sufficient energy and the pre-exponential factor is the frequency of recurrence of the configuration favorable to the reaction, itself proportional to a configurational probability in a chaotic system. This minimalist yet rigorous mathematical approach makes it possible to bypass certain questionable postulates of more sophisticated theories and clarifies the meaning of the different types of energies used activation energy, threshold energy and chemical energy