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.
Highlights
Activated jump between neighboring sites of local minimum energy is the very fundamental process in modeling atomistic diffusion
The electronic contribution to migration enthalpy is ignored, but the ion–ion interaction energy needs to be taken into account since configuration of the atom at the saddle point is appreciably closer to its neighbors
The aim of the present model is to extend the approaches of Burke1 and Shewmon5 to make the physical nature of the entropy and enthalpy of migration clear
Summary
Activated jump between neighboring sites of local minimum energy is the very fundamental process in modeling atomistic diffusion. He considered that the normal modes of initial atomic vibration being randomly distributed would become in phase, making the vibration amplitude of the atom become very large after a period of time He further suggested that only the modes causing the atom and the neighboring vacancy to move relative to each other would contribute to a diffusive motion. The average jump frequency (ω) for any given atom can be expressed as ω nsv Nw. To a first approximation, the electronic contribution to migration enthalpy is ignored, but the ion–ion interaction energy needs to be taken into account since configuration of the atom at the saddle point is appreciably closer to its neighbors. The aim of the present model is to extend the approaches of Burke and Shewmon to make the physical nature of the entropy and enthalpy of migration clear
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
