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Rotation of ethanol molecules in the ethanol—water mixtures studied by light scattering

1978; Elsevier BV; Volume: 31; Issue: 3 Linguagem: Inglês

10.1016/0301-0104(78)85127-1

1873-4421

Wolfgang Schindler,

Thermodynamic properties of mixtures

Measurements of depolarized Rayleigh and depolarized and polarized Raman spectra of liquid ethanol—water mixtures are reported from which single- and many-particle reorientation times are deduced. The ratio of correlation times τRay/ τRam indicates strong static order of the ethanol molecules down to ethanol mole fractions ≈0.35. The polarized spectra are analyzed within the framework of a rapid modulation theory of vibrational frequencies. The modulation time τc is found to decrease substantially for ethanol mole fractions less than 0.35. Reorientation times are compared to literature values. The differences are explained considering anisotropic reorientation of the ethanol molecules. The experimental results suggest that quasistatic water—ethanol complexes do not exist at any concentration.