Investigation of the Structure of Ethanol–Water Mixtures by Molecular Dynamics Simulation I: Analyses Concerning the Hydrogen-Bonded Pairs

Citations Over TimeTop 10% of 2015 papers

Abstract

Series of molecular dynamics simulations for ethanol-water mixtures with 20-80 mol % ethanol content, pure ethanol, and water were performed. In each mixture, for ethanol the OPLS force field was used, combined with three different water force fields, the SPC/E, the TIP4P-2005, and the SWM4-DP. Water potential models were distinguished on the basis of deviations between calculated and measured total scattering X-ray structure factors aided by ethanol-water pair binding energy comparison. No single water force field could provide the best agreement with experimental data at all concentrations: at the ethanol content of 80% the SWM-DP, for 60 mol % the SWM4-DP and the TIP4P-2005, whereas for the 40 and 20 mol % mixtures TIP4P-2005 water force field provided the closest match. Coordination numbers and hydrogen bonds/molecule values were calculated, revealing that the oxygen-oxygen first coordination numbers strongly overestimate the average number of hydrogen bonds/molecule. The center-of-molecule distributions indicate that the ethanol-ethanol first coordination sphere expands with increasing water concentration while the size of the first water-water coordination sphere does not change. Various two and three-dimensional distributions were calculated that reveal the differences between simulations with different water force fields. Detailed conformational analyses of the hydrogen-bonded pairs were performed; drawings of the characteristic molecular arrangements are provided.

Related Papers

• → Development and Testing of the OPLS-AA/M Force Field for RNA(2019)98 cited
• → Molecular Dynamics Simulations of Proteins: Can the Explicit Water Model Be Varied?(2007)71 cited
• → Optimized all-atom force field for alkynes within the OPLS-AA framework(2021)15 cited
• → Optimisation of OPLS–UA force-field parameters for protein systems using protein data bank(2010)14 cited
• → Condensed phase properties of n-pentadecane emerging from application of biomolecular force fields(2020)4 cited