Concentration (D2O in H2O) and temperature Raman study of the molecular interactions in the OD stretching spectra of D2O and D2O/H2O mixtures using the fourier deconvolution technique

The OD stretching spectra of D2O for temperatures from 5 to 90°C and for concentrations (D2O in H2O) from 100 to 10 mol‐% were studied. These spectra were treated by means of the Fourier deconvolution technique for the first time. Using the positions of the resolved components the coupling constants for intra‐ and inter‐molecular and Fermi resonance interactions and all parameters according to the presented model, for all investigated temperatures, were evaluated. A gradual decrease in all interactions was observed in the concentration study, in accordance with expectations and in agreement with the results for dilute solutions of H2O in D2O. The temperature behaviour of the coupling constants and other parameters were in accordance with the corresponding data for H2O. The only exception is the temperature behaviour of the intramolecular coupling constant. The greater mass of the D atom is one of the probable reasons that lead to the smaller sensitivity of OD frequency to the hydrogen bond fluctuations. All the results verify the assignments and assumptions made according to the model presented and support the continuous model for the water structure.