RAMAN-STUDY OF DIOXANE-D2O MIXTURES BY ANALYSIS OF THE O-D BAND-STRUCTURE

Changes in the isotropic and anisotropic component profiles of the O-D stretching bands of D2O were studied in the range 0-0.5 mole fraction (m.f.) of 1,4-dioxane. The contribution of the C-H Raman band of diox ane was subtracted using Raman spectra of dioxane-water mixtures in th e same concentration range. A Fourier deconvolution technique was empl oyed to resolve the overlapped components in the spectra. The informat ion on the positions of the components in the isotropic spectra was us ed to fit them with symmetric components of mixed Gaussian-Lorentzian type. The wavenumbers of the resolved components in the isotropic and anisotropic spectra and the ratio of the intensities of the symmetric Fermi resonance components in the isotropic spectra were used to deter mine the concentration dependence of intermolecular, intramolecular an d Fermi resonance parameters. The intermolecular and intramolecular in teraction constants do not change significantly up to about 0.07-0.10 m.f. of dioxane and then gradually decrease. The Fermi resonance const ant W does not change noticeably over the concentration range studied. The wavenumbers of the unperturbed O-D oscillator exhibits two differ ent rates of increase with concentration of dioxane. The observed vari ations in the analysed parameters are interpreted in terms of hydropho bic hydration, hydrophobic interaction and hydrogen bonding in dioxane -water mixtures.