Monte Carlo simulations were performed on lattice gas systems with Coulombic interactions. Emphasis was placed on two lattice gases. The first consists of both mobile anions and cations while the second is composed of mobile anions and a random distribution of fixed cations. Comparisons are made to a strictly repulsive lattice gas. The addition of attractive forces is shown to significantly retard particle motion relative to the repulsive system. In the mobile-anion, mobile-cation system, at temperatures high enough to suppress ion clustering, the effect of backward correlations on the particle diffusivity is found to be similar to that for the strictly repulsive system. In the mobile-anion, fixed-cation system, however, backward correlations are much stronger due to the presence of immobile Coulomb traps. Both systems deviate from Nernst-Einstein behavior. The mobile-anion, mobile-cation system exhibits diminished conductivity (Haven ratio > 1) due to the migration of neutral ion pairs, whereas the mobile-anion, fixed-cation system exhibits slightly enhanced conductivity (Haven ratio < 1) due to the mutual repulsions between mobile charge carriers. The results of these simulations are discussed in terms of multiple timescale behavior, specifically including Funke's jump relaxation model, and observations on relaxation times are reported.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry