Description of deviations from Arrhenius behavior in chemical kinetics and materials science

The Arrhenius law has been used successfully to describe the temperature dependence for a considerable number of rate processes in many areas of molecular science. In order to provide a description of non-Arrhenius processes, we illustrate a formula permitting to evaluate prototypes systems where the temperature dependence of the rate constant is concave (super-Arrhenius), convex (sub-Arrhenius), or may change the curvature (anti-Arrhenius) in the semilog plots against reciprocal temperature. Modern experimental techniques and theoretical approaches are providing an ample phenomenology for deviations especially at low temperatures.