X-ray absorption fine structure spectroscopy in the energy region near (within approximately
\(\pu{100 eV}\)) an absorption edge.
Notes: - XANES results from interference in multiple scattering of low-energy photoelectrons by surrounding atoms. It provides information on the local coordination environment, oxidation state, molecular orbitals, hybridization, and band structure (unoccupied electronic states).
- XANES measurements usually start some \(\pu{10 eV}\) before the core-level binding energy (the absorption edge) of the emitting atoms, because in many cases pre-edge features are used to identify chemical bonds, e.g. \(\uppi\!^*\) resonances (excitation into lowest unoccupied molecular orbitals) in C K-edge spectra of polymer samples.
- Usefully sharp absorption edges are commonly observed in X-ray absorption spectra, although broader increases can be observed for some inner-shell excitations with short lifetimes.
Source:
PAC, 2020, 92, 1781. 'Glossary of methods and terms used in surface chemical analysis (IUPAC Recommendations 2020)' on page 1795 (https://doi.org/10.1515/pac-2019-0404)