Palestra: A look from a different perspective: XAS vs. XRD
07 de julho @ 14:00 - 17:00
X-ray Absorption Spectroscopy and X-ray Diffraction as complementary tools to understand chemical and structural features of materials.
Gabriele Giuli, associate professor at the University of Camerino (Italy) Abstract: The huge work on the development of new functional materials in the last years has led to the need of a full structural characterization to accurately understand the relationship between structural and physical properties. Most of the crystalline materials are routinely characterised by using X-ray diffraction. This approach allows 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 in 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. Palestrante: Gabriele Giuli Data: 07 de julho de 2025 – 14h Local: Auditório A5 – 1° Andar
Gabriele Giuli, associate professor at the University of Camerino (Italy) Abstract: The huge work on the development of new functional materials in the last years has led to the need of a full structural characterization to accurately understand the relationship between structural and physical properties. Most of the crystalline materials are routinely characterised by using X-ray diffraction. This approach allows 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 in 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. Palestrante: Gabriele Giuli Data: 07 de julho de 2025 – 14h Local: Auditório A5 – 1° Andar