Title: A look from a different perspective: XAS vs. XRD
X-ray Absorption Spectroscopy and X-ray Diffraction as complementary tools to understand chemical and structural features of materials.
Abstract:
The huge work on the development of new functional materials in the last years has led to the need of full structural characterization to accurately understand the relationship between structural and physical properties. Most of the crystalline materials are routinely characterized by using X-ray diffraction. This approach allows us to obtain accurate information on the average structure but may often neglect any deviation from this description. As a matter of fact, many interesting properties derive from short-range order phenomena which are quite difficult to understand by using standard approaches. X-ray absorption spectroscopy (XAS) is a powerful technique which allows to obtain chemical and structural information on specific elements. The strength of XAS relies in the fact that it can be applied to any kind of material and almost any chemical element, obtaining information on oxidation state and local structure without any constraint related to the average structure.
The seminar will be divided into two parts. I will first introduce the basics of XAS with details about X-ray Near Edge Spectroscopy (XANES) and Extended X-ray Absorption Fine Structure (EXAFS). This part will include some details about synchrotron radiation and measurement strategies and the most common methods to interpret the results. The introductory part will be followed by a few examples regarding the application of XAS to crystalline and amorphous materials.
Gabriele Giuli é professor associado da Universidade de Camerino (Itália), onde leciona Mineralogia. Sua atividade de pesquisa é voltada para a determinação do papel estrutural e do estado de oxidação de dopantes em estruturas cristalinas e em vidros de silicato, em espectroscopia de absorção de raios-X e na síntese de cristais e vidros. Co-autor de cerca de 100 publicações e co-editor de um livro sobre técnicas relacionadas à espectroscopia de radiação síncrotron, ele está atualmente envolvido em projetos que investigam a recuperação de materiais críticos a partir de resíduos (incluindo baterias) e sobre a síntese de um simulador de regolito lunar.
Dia: 08/07/2025
Horário: 10h
Local: Instituto de Geociências, sala 218.
Palestra presencial. Em inglês.
