The hydrophobic effect is essential to life. In previous studies, molecular dynamics simulations using a single-site multipole model for liquid water (referred to as SSDQO1) were shown to reproduce the anomalous concentration dependence of ethanol-water mixtures as well as structural data from neutron diffraction, in contrast to four typical site models for water. In particular, SSDQO1 reproduced the distinctive minimum in the partial molar volume of ethanol at low mole fraction of ethanol, which was an important result in our current understanding of the hydrophobic effect. The simulations indicated that breakdown of the ordered hydration shell of hydrophobic groups was responsible for the minimum, although its position and depth did not match experiment exactly. Recently, since single-site multipole models can better describe the electrostatic potential of a water molecule, especially the large quadrupole and out-of-plane character of the charge distribution, we further improved the parameterization (referred to as SSMP). In the current study, the concentration dependence of ethanol-water mixtures is re-examined using the SSMP model for water, as an important assessment of its solvation properties.<br/>

Hydrophobic effect in molecular dynamics simulations of water/ethanol mixtures using single-site multipole water

256th National Meeting (2018)

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