Raman study of dioxane–D2O mixtures by analysis of the O–D band structure

Abstract

AbstractChanges 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 dioxane was subtracted using Raman spectra of dioxane—water mixtures in the same concentration range. A Fourier deconvolution technique was employed to resolve the overlapped components in the spectra. The information on the positions of the components in the isotropic spectra was used 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 determine the concentration dependence of intermolecular, intramolecular and Fermi resonance parameters. The intermolecular and intramolecular interaction constants do not change significantly up to about 0.07–0.10 m.f. of dioxane and then gradually decrease. The Fermi resonance constant W does not change noticeably over the concentration range studied. The wavenumbers of the unperturbed O–D oscillator exhibits two different rates of increase with concentration of dioxane. The observed variations in the analysed parameters are interpreted in terms of hydrophobic hydration, hydrophobic interaction and hydrogen bonding in dioxane–water mixtures.