First principles calculation of Raman spectra: relationships between structure and vibrations

Simona Ispas (1)

1 L2C - Laboratoire Charles Coulomb

In recent years, Raman spectroscopy has become a tool of choice for the structural analysis of glasses, due to its simplicity and the low cost of acquisition. However, the broad and overlapping peaks observed in the spectra result in a phenomenological and often qualitative interpretation. In order to improve the analysis of Raman spectra, and to start to obtain a more quantitative interpretation, one needs to identify the exact contributions arising from individual structural units. We have used first-principles and combined classical/first-principles approaches to create representative atomistic models of some simple binary soda- and lime-silicates, as well as for some ternary aluminosilicates. Within the density functional theory framework, we have calculated the vibrational density 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 made possible to identify the signatures of the various constituents of the glasses in the spectra, as for example the Qi species. The obtained correlations can be then used to better assign the main bands present in the spectra of more complex silicate glasses.

Domaines: Systèmes désordonnés et réseaux de neurones [cond-mat.dis-nn]; Science des matériaux [cond-mat.mtrl-sci]

Simona Ispas. First principles calculation of Raman spectra: relationships between structure and vibrations. Glass and Optical Materials Division Annual Meeting 2016, May 2016, Madison, United States. ⟨hal-01938487⟩