Simple computing of the viscosity of water–dioxane mixtures, according to a fluctuating SPC/E-Ih interstitial model

5 years ago

Simple computing of the viscosity of water–dioxane mixtures, according to a fluctuating SPC/E-Ih interstitial model

Anis Ghazouani, Jalel M'halla

In this contribution, we propose a new simple and fast computing approach to model liquid water and water-1,4 dioxane mixture, which is intermediate between molecular dynamics calculation and lattice fluid H-bonding theory in which water molecules are arranged according to a fluctuating hexagonal Ih network. It generalizes the interstitial mixture models of Samoilov and Pauling by increasing the number of spatial configurations into the space of phases due to the addition of rotations and vibrations of the molecules around their equilibrium positions. The potential energy landscape is determined by the generalization of the Madelung's approach to the molecular water network using simple point charge model (SPC/E partial charges). This approach allows useful predictions as the possibility of incorporation of a molecule of dioxane in the water Ih-network or how some cooperative dynamic jumps (site - hole) of water molecules, contribute to lower Eyring's activation energies and thus to facilitate the viscous flow. © 2017 Wiley Periodicals, Inc. Cooperative dynamic jumps of water molecules from lattice sites toward adjacent holes into the fluctuating SPC/E-Ih network facilitate the viscous flow by lowering the Eyring's activity energy. In the case of the water–dioxane dilute mixture, dioxane molecules are incorporated according to a mechanism of substitution of the cluster “(H2O)6” by a “1,4-dioxane” molecule. This incorporation explains the quasi-linear variation of the global viscosity activation energy of the mixture with the molar fraction of dioxane.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/jcc.24841