The Soret effect, as it occurred in the diffusion of solutes in crystals, was analyzed by using the principle of microscopic reversibility. An approach was developed for interpreting and computing Q*, the heat of transport. In order to compute the transport of energy during the diffusion jump process, and thus Q*, the processes of thermal activation to the transition state, and the decay from the transition state, were considered to be inverses. Therefore, the overall process was reduced to the analysis of the purely mechanical decay process. Molecular statics and dynamics were suggested to be a means for simulating the decay process, and the case of C diffusion in body-centred cubic α-Fe was analyzed as an example. The results showed that, for the case Q* ≈ -Qm, where Qm was the activation energy for C diffusion, this was in agreement with published experimental evidence. Thus, both the sign and the magnitude of Q* were correctly predicted. Other cases, such as the diffusion of substitutional solutes and vacancies, were also considered using this approach.

The Soret Effect in Diffusion in Crystals. R.J.Asaro, D.Farkas, Y.Kulkarni: Acta Materialia, 2008, 56[6], 1243-56