Topological properties of interfacial hydrogen bond networks
Ruiyu Wang, Mark DelloStritto, Michael L. Klein, Eric Borguet, Vincenzo Carnevale
Abstract
Hydrogen bonds play a crucial role in the anomalous behavior of water. While the properties of individual hydrogen bonds have been extensively studied, the topological characteristics of the resulting hydrogen bond network remain less explored. In this study, we employ molecular dynamics simulations to examine various aqueous interfaces, uncovering an increased number of hydrogen bonds parallel to surfaces compared to bulk water. To quantify the topology of these networks, we introduce estimators for network percolation and dimensionality. Our findings reveal that the elevated proportion of hydrogen bonds parallel to the interface significantly influences network connectivity, reducing both the number of water layers and the distance from the surface at which the network achieves full connectivity. Consequently, hydrogen bond networks at interfaces exhibit more ``two-dimensional'' characteristics than those in bulk water due to high local water density and the competition between water-water hydrogen bonds and water-surface interactions.