Abbas Alshehabi
ABSTRACT X‐ray absorption fine structure (XAFS), comprising X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS), is a powerful experimental technique for probing oxidation state, coordination symmetry, and local atomic structure in complex materials. In particular, XANES features such as edge position, pre‐edge intensity, and white‐line amplitude provide chemically sensitive information widely used in chemical‐state analysis. This work presents a compact analytical framework that links these experimentally observable spectral features to oxidation state, unoccupied electronic states, coordination geometry, and structural disorder using first‐principles physical relationships. The model captures oxidation‐state‐dependent edge shifts, symmetry‐controlled pre‐edge behavior, white‐line scaling with d‐hole population, and EXAFS amplitude dependence on coordination number and bond length. The framework is further extended to mixed‐valence systems through linear‐combination expressions describing spectral superposition and intermediate centroid shifts, enabling analytical interpretation of Fe 2+ /Fe 3+ mixtures and related multivalent materials. By bridging fundamental XANES/EXAFS physics with practical spectral interpretation, the proposed approach provides a transparent, simulation‐independent interpretive tool for chemical‐state identification in environmental, geological, catalytic, and energy materials where reference spectra or advanced computational resources may be limited.