Insight into understanding the jump frequency of diffusion in solids

Abstract

In view of the diversity and ambiguity of the interpretation of the physical nature contributing to the jump frequency of diffusion in solids, the fundamental of jump frequency is reexamined with special attention toward enthalpy and entropy aspects. The present model, extending the approaches of Burke and Shewmon, provides an insight into understanding the jump frequency of diffusion in solids. The entropy term involved in the frequency or pre-exponential factor basically stems from the change in the vibration frequency of the atoms in a transitional complex. Migration enthalpy is the sum of the thermal energy required for the vibration amplitude of the jumping atom to reach the critical amplitude and the elastic energy of minimal local deformation developed in a transitional complex.