A theory of electrical conductivity of non-equivalent molten salts

The electrical conductivity of non-equivalent molten salts has been theoretically investigated based on the linear response theory, which is an extension from the expression for equivalent molten salts as we have developed in the previous papers. The velocity correlation functions are expressed in terms of pair potentials and pair distribution functions. Using these functions and Langevin equations for ions, the relations among the conductivity coefficients are obtained. It is shown that the ratio of partial conductivities σ⁺/σ^?  is equal to |z ⁺|m ^? /|z ^? |m ⁺, which is an extensive expression from the inverse mass ratio in the case of equivalent molten salts. Numerical results for molten CaCl₂ and AlF₃ are presented, which agree well with the results of experiments and molecular dynamics simulations.