Promotionsvortrag Physik: Aspherical Form-Factor Modeling and Data Reconstruction for X-Ray Powder Diffraction

Ankündigung des Promotionsvortrags von: Herrn Kárel García Medina

X-ray diffraction (XRD) is a powerful tool for the characterization of crystalline materials, providing information on crystal structure, phase composition, and other structural parameters. In XRD analysis, an a priori model of the expected diffraction pattern is commonly formulated from a proposed crystal structure and subsequently refined against experimental data. Conventionally, scattering form factors are assumed to be independent and spherically symmetric. This Independent Atom Model (IAM) simplification reduces computational complexity but can lead to significant discrepancies between calculated and experimental data, particularly for complex organic molecular structures. Additionally, technical and instrumental limitations affecting the quality of experimental data can further complicate the refinement process. In this thesis, Aspherical Atomic Model (AAM) scattering form factors were integrated into a computational workflow for X-ray diffraction analysis and structure refinement to improve the accuracy of structural models and the reliability of the results. Physics-driven data-enhancement techniques were also developed, implemented, and applied to improve the quality of experimental data and thereby support the refinement process. The results demonstrate that AAM scattering form factors and advanced data-processing techniques can significantly improve the accuracy of XRD analysis and structure refinement, even for low-resolution powder data, leading to more reliable structural results.

(Vortrag auf Englisch)

Dem Vortrag schließt sich eine Diskussion von 15 Minuten an. Vortrag und Diskussion sind öffentlich. Diesen Verfahrensteilen folgt ein nicht öffentliches Rigorosum von 45 Minuten.