A Relationship between Prefactor and Activation Energy for Diffusion

Very often a relationship is observed between activation energies, Q, of diffusion and the corresponding prefactors, D0. Contrary to the Zener‐Wert relation, where activation energy and prefactor of different species migrating in the same matrix are compared, one species diffusing in a matrix with different defects or slightly varying composition is considered. It is shown that a linear relationship between In D0 and Q very often exists due to the special form of the Arrhenius equation. The slope of the corresponding graph is close to 1/kTa, where Ta is the average temperature of the range covered by the experiments. Experimental results are compiled and compared with this prediction.