Open AccessHydrogen Bonding and Dielectric Spectra of Ethylene Glycol–Water Mixtures from Molecular Dynamics Simulations
Author(s) -
Alexander Kaiser,
Marcel Ritter,
Renat R. Nazmutdinov,
Michael Probst
Publication year - 2016
Publication title -
the journal of physical chemistry. b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 392
eISSN - 1520-6106
pISSN - 1520-5207
DOI - 10.1021/acs.jpcb.6b05236
Subject(s) - ethylene glycol , molecular dynamics , slowdown , relaxation (psychology) , hydrogen bond , spectral line , dielectric , hydrogen , chemistry , materials science , chemical physics , molecule , analytical chemistry (journal) , thermodynamics , computational chemistry , organic chemistry , physics , psychology , social psychology , optoelectronics , astronomy , political science , law
Mixtures of ethylene glycol with water are a prominent example of media with variable viscosity. Classical molecular dynamics simulations at room temperature were performed for mixtures of ethylene glycol (EG) and water with EG mole fractions of x E = 0.0, 0.1, 0.2, 0.4, 0.6, 0.9, 1.0. The calculated dielectric loss spectra were in qualitative agreement with experiment. We found a slightly overestimated slowdown of the dynamics with increasing EG concentration compared to experimental data. Statistics of the hydrogen bond network and hydrogen bond lifetimes were derived from suitable time correlation functions and also show a slowdown in the dynamics with increasing x E . A similar picture is predicted for the time scales of EG conformer changes and for molecular reorientation. A slight blue shift was obtained for the power spectra of the molecular center of mass motion. The results were used to give a qualitative interpretation of the origin of three different relaxation times that appear in experimental complex dielectric spectra and of their change with x E .