Electrostatic Correlations and Non-Electrostatic Effects on Ion Dynamics in Alternating Current Voltages*

Abstract

RESUMO -We present a modified Poisson-Nernst-Planck (mPNP) model to include both non-electrostatic effects and electrostatic correlations on ion dynamics near charged parallel blocking electrodes. The first contribution appears directly on ion chemical potential, whereas the latter is addressed by a modified Poisson equation. The model consists in a partial-differential-algebraic equation system, solved by the DASSLC code, implemented in EMSO simulator. Monte Carlo simulation results were properly described without the aid of fitting parameters. The model predicts overscreening for 2:1 electrolytes, which was not accessed by classical PNP-like approaches. Alternate voltage simulations show a meaningful effect of electrostatic correlations on mobile charge dynamics for 2:1 electrolytes, where ion-ion correlations are stronger near the electrodes. This is the first report accounting for electrostatic correlations on ion dynamics via PNPlike models under alternating current (ac) voltages to the best of our knowledge.