Modified Arrhenius Equation in Materials Science, Chemistry and Biology

The Arrhenius plot (logarithmic plot vs. inverse temperature) is represented by a straight line if the Arrhenius equation holds. A curved Arrhenius plot (mostly concave) is usually described phenomenologically, often using polynomials of T or 1/T. Many modifications of the Arrhenius equation based on different models have also been published, which fit the experimental data better or worse. This paper proposes two solutions for the concave-curved Arrhenius plot. The first is based on consecutive A→B→C reaction with rate constants k₁ ≪ k₂ at higher temperatures and k₁ ≫ k₂ (or at least k₁ > k₂) at lower temperatures. The second is based on the substitution of the temperature T the by temperature difference T - T₀ in the Arrhenius equation, where T₀ is the maximum temperature at which the Arrheniusprocess under study does not yet occur.