Skip to Main content Skip to Navigation

Étude de la structure locale d’oxydes alcalins par diffusion Raman des rayons X

Abstract : The oxygen is an abundant element on Earth, which is able to make oxide by bonding with many other elements. Among the diverse oxides, alkali borates and silicates are studied in many scientific fields for their properties, which requires to improve the understanding of both their crystalline and vitreous structures. X-ray Raman Scattering (XRS) is an adequate technique to study the local structure of those compounds as it allows measurements carried out on light elements even using a complex sample environment, like high-pressure or high-temperature device. XRS requires the development of theoretical tools in order to interpret the experimental spectra, we have thus developed a computational code to simulate XRS spectra at K edges. A good agreement between theoretical and experimental spectra at all the edges of references compounds composed of light elements was found, allowing us to use this code to interpret data on alkali borates and silicates. We mainly focused on the oxygen local environment in alkali borates and silicate in order to understand the local and medium range order of the structure of vitreous compounds using crystalline compounds as references. We manage to evidence some specific spectral signature related to the symmetry of the oxygen environment. Some spectral signature can be followed during in situ high-pressure measurements as they give information on the compounds behavior under pressure and the structural changes it undergoes. Using those spectral signatures, we were able to follow the behavior of two lithium borates under pressure and to come up with a densification mechanism depending on the structural oxygen packing.
Complete list of metadatas

Cited literature [230 references]  Display  Hide  Download
Contributor : Abes Star :  Contact
Submitted on : Friday, October 16, 2020 - 5:15:09 PM
Last modification on : Saturday, October 17, 2020 - 3:32:21 AM


Version validated by the jury (STAR)


  • HAL Id : tel-02969633, version 1


Emmanuelle De Clermont Gallerande. Étude de la structure locale d’oxydes alcalins par diffusion Raman des rayons X. Matière Condensée [cond-mat]. Sorbonne Université, 2019. Français. ⟨NNT : 2019SORUS070⟩. ⟨tel-02969633⟩



Record views


Files downloads