The self-diffusion coefficients of the ionic species in melts were evaluated by using the Green-Kubo formulae. The evaluation was based upon a simple model in which the dynamics of a 2-component system were exploited. This related the self-diffusion coefficients to pair potential and partial structure factors of the melt via frequency sum rules of the velocity auto-correlation function. The results explained an increase, with increasing K content, in the difference between the 2 diffusion coefficients; as observed using molecular dynamics methods. This difference was attributed to the differing structural back-scattering of ions, as influenced by their screening due to the presence of valence electrons.

R.Sharma, K.Tankeshwar: Journal of Physics - Condensed Matter, 1997, 9[29], 6191-7