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Résumé:

In recent years, Raman spectroscopy has become a toolof choice for the structural analysis of glasses, due to its simplicity and thelow cost of acquisition. However, the broad and overlapping peaks observedin the spectra result in a phenomenological and often qualitativeinterpretation. In order to improve the analysis of Raman spectra, and to startto obtain a more quantitative interpretation, one needs to identify the exactcontributions arising from individual structural units.We have used first-principles and combined classical/first-principlesapproaches to create representative atomistic models of some simple binarysoda- and lime-silicates, as well as for some ternary aluminosilicates. Withinthe density functional theory framework, we have calculated the vibrationaldensity of states as well as the IR and Raman spectra of these glass models,and we have found a good agreement with the experimental spectra.The knowledge of the theoretical spectra and the atomic structure has madepossible to identify the signatures of the various constituents of the glasses inthe spectra, as for example the Qi species. The obtained correlations can bethen used to better assign the main bands present in the spectra of morecomplex silicate glasses.