CAMPUS è l'Archivio istituzionale delle pubblicazioni scientifiche dell’Università di Camerino. E’ un sistema aperto, pubblico e interoperabile che raccoglie, conserva ed espone i dati relativi alle attività e ai prodotti della ricerca dell’Ateneo con lo scopo di migliorarne la visibilità e di favorirne l’impatto a livello nazionale e internazionale.
EnglishThe preedge features in a system with `even' symmetry, apart from quadrupolar transition contribution, are mainly dipolar in character, associated with the existence of unoccupied states made up of mixed cation-4p with higher-neighboring cation-3d orbitals, and reflect the density of states due to the medium-range order of the system. In `odd' symmetry materials these preedge features are the result of a transition from the 1s to a final density of states of p symmetry due to an unsymmetrical mixing of the ligand wave functions with the central cation 3d orbitals, similar to atetrahedral configuration. These results are validated for Fe as a photoabsorber by comparing XAS spectra of Fe2SiO4 (fayalite) to ab initio full multiple scattering calculations at the Fe K edge, but pertain to all systems containing sixfold-coordinated cations.
Scheda prodotto non validato
Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo
| Titolo: | Symmetry role on the preedge X-ray absorption fine structure at the metal K-edge |
| Autori: | |
| Data di pubblicazione: | 2001 |
| Rivista: | |
| Abstract: | The preedge features in a system with `even' symmetry, apart from quadrupolar transition contribution, are mainly dipolar in character, associated with the existence of unoccupied states made up of mixed cation-4p with higher-neighboring cation-3d orbitals, and reflect the density of states due to the medium-range order of the system. In `odd' symmetry materials these preedge features are the result of a transition from the 1s to a final density of states of p symmetry due to an unsymmetrical mixing of the ligand wave functions with the central cation 3d orbitals, similar to atetrahedral configuration. These results are validated for Fe as a photoabsorber by comparing XAS spectra of Fe2SiO4 (fayalite) to ab initio full multiple scattering calculations at the Fe K edge, but pertain to all systems containing sixfold-coordinated cations. |
| Handle: | http://hdl.handle.net/11581/102998 |
| Appare nelle tipologie: | Articolo |
File in questo prodotto:
http://hdl.handle.net/11581/102998
Copyright © 2021