Neutron Diffraction Study on Microinhomogeneities in Ethanol-Water Mixtures

Neutron diffraction with isotopic substitution measurements have been made at room temperature on seven isotopically substituted ethanol-water mixtures at 0.1, 0.2 and 0.4 ethanol mole fractions, respectively, from which nine composite partial structure factors, HH, HX and XX (X denotes the weighted sum of non-substituted atoms) were derived on water-water, water-ethanol and ethanol-ethanol interactions for each of the solutions. The partial structure factors were then subjected to an empirical potential structure refinement simulation to derive all site-site pair correlation functions. An origin of the so-called microinhomogeneities in ethanol-water mixtures has been established at the molecular level on the basis of the pair correlation functions, which probably underlines the mechanism of anomalous behaviors in physico-chemical quantities and alcohol-induced denaturation of proteins in ethanol-water mixtures.