Molecular dynamics simulations of the properties of water-methanol mixtures. Effects of force fields

Abstract

Isothermal-isobaric molecular dynamics simulations are used to examine the microscopic structure and some properties of water-methanol liquid mixture. The TIP4P/2005 and SPC/E water models are combined with the united atom TraPPE and the all-atom force field model for methanol. Our principal focus is to evaluate the quality of predictions of different combinations of model force fields concerning the composition dependence of basic properties of this system. Specifically, we explored the composition effects on density, excess molar volume and excess entropy, as well as on the surface tension and static dielectric constant. In addition, the structural properties are described in terms of the coordination numbers and the average number of hydrogen bonds between molecules of constituent species. Finally, the composition dependence of self-diffusion coefficients of the species is evaluated. All theoretical predictions are tested with respect to experimental data.

Competing interactions near the liquid-liquid phase transition of core-softened water/methanol mixtures

“…It is fully miscible for all compo-sitions, and methanol molecules are fully integrated in water's hydrogen bond network [59]. These solutions present anomalies in some of their thermodynamic properties, which are strongly dependent on the solute concentration and have thoroughly investigated experimentally and by computational modeling [60,61,62,63,64,65]. On the other hand, to the best of our knowledge, the influence of amphiphilic solutes on the liquid-liquid critical region has not being investigated so far.…”

Interfacial and bulk properties of concentrated solutions of ammonium nitrate

“…Both SPCE/F and TIP4P/2005 reproduce very well the surface tension of water at 298.15 K. [58][59][60][61][62][63] In this article, we compare the results from the SPCE/F and TIP4P/2005 models with the simple and commonly used SPC/E model to gain a clear overview on the performance and transferability of ion parameters to the three water models. 64,65 We represent the ammonium and nitrate ions (NH 4 + and…”

On the properties of methanolic NaCl solution by molecular dynamics simulations

“…The present contribution is a part of our ongoing project focused on the theoretical exploration of properties of ionic solutes in water-alcohol solvents of variable composition. At the first stage, watermethanol model mixtures have been explored in this laboratory [21][22][23][24], continuing several previous studies of this kind of systems, see e.g., [25][26][27][28][29][30][31][32] and respective references in the above cited works. Still, there remains room for additional insights, having in mind the recent novel modelling of liquid methanol [33,34].…”