Dynamics of Water-Ethanol Mixtures Studied by Light Scattering.

Brillouin scattering of water-ethanol binary mixtures have been measured in the temperature range from room temperature to 343 K as a function of ethanol concentration. A maximum appears at 12 ethanol mol% in the sound velocity and at about 50 mol% in the absorption coefficient α/f2 at room temperature. Raman scattering of heavy water-ethanol mixtures was also measured at room temperature as a function of concentration. The concentration range from 0–100 mol% is divided into three ranges and the behavior of the acoustic properties was discussed with three cluster models; the circular clusters are dominant in the concentration range of 0–12 mol%, layered clusters in the range of 12–50 mol%, pure ethanol chain clusters in the range of 50 –100 mol% at room temperature. These results are consistent with the concentration variation of OH stretching band of Raman spectra and the results in literatures. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]