Conductance of Cs⁺ ion in water: Molecular dynamics simulation

Abstract

The continuum theory of Hubbard-Onsager predicts for the friction coefficients Δζ the following behavior: Δζ>0 and ∂Δζ/∂P<0. In contrast to Hubbard-Onsager theory, experimental observations on Cs⁺ ion in water show that at low temperatures Δζ<0 and ∂ζ/∂P>0. To explain the observed behavior of Δζ Nakahara et al. proposed the passage through cavities (PTC) mechanism. We performed a molecular dynamics computer simulation to determine if the PTC mechanism is responsible for the observed behavior of Δζ. No passage through cavities was observed. Molecular dynamics computer simulations were performed on Cs⁺ ion in water at temperature of 268 K and densities of 1.00 and 1.083 g-cm⁻³. Our results indicate that the observed behavior of Δζ for Cs⁺ ion is related to the difference in the reorientation times of water molecules in the solvation shell and in the bulk.