Abstract
In this paper, we present molecular dynamics study of the fast proton transport in water confined between hydroxylated silica surfaces. Empirical valence bond (EVB) method was introduced to our MD simulation system for reproducing Grotthuss mechanism (proton hopping). We evaluated the enhancement of Grotthuss mechanism by counting the number of hopping events in confined and bulk water. The number in confined water increases by 4-6 times compared to bulk value, suggesting the enhancement of proton transport. Furthermore, the activation energy of Grotthuss mechanism was calculated from Arrhenius plot for the number of hopping events. As a result, the activation energy decreases from 4.5 kcal/mol in bulk water to 3.4 kcal/mol in confined water, which leads to the fast proton motion.
