Reductionist approach to chemical rate constants using conditional energy probabilities

Abstract: Different rate theories yielded similar forms of rates constants consistent with the phenomenological Arrhenius law, although they were derived from various branches of physics including classical thermodynamics, statistical and quantum mechanics. This convergence supports the validity of the Arrhenius law but also suggests the existence of an even simpler underlying principle. A reductionnist 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 while 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.