Chinese Acad Sci, Inst High Energy Phys, Beijing Synchrotron Radiat Facil, Beijing 100039, Peoples R China
; Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy
; Univ Camerino, Dipartimento Sci Terra, I-62032 Camerino, MC, Italy
; Univ Roma Tre, Dipartimento Sci Geol, I-00146 Rome, Italy
The pre-edge 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 np with higher-neighboring cation- (n-1) d orbitals, and reflect the density of states due to the medium-range order of the system, while in "odd" symmetry materials these pre-edge features are the result of a transition from the Is to a final density of states of p symmetry due to an unsymmetrical mixing of the ligand wave functions with the central cation d orbitals. In the latter case, they contain not only the p but also the d base of orbitals, similar to a tetrahedral configuration. These results are validated for Fe as a photoabsorber by comparing x-ray absorption near-edge spectra of Fe2SiO4 (fayalite) and Fe2O3 (hematite) to ab initio full multiple scattering calculations at the Fe K edge, but pertain to all systems containing sixfold-coordinated cations. (C) 2001 American Institute of Physics.
Wu ZY,Xian DC,Wu, ZY,et al. Symmetry dependence of x-ray absorption near-edge structure at the metal K edge of 3d transition metal compounds[J]. APPLIED PHYSICS LETTERS,2001,79(12):1918-1920.
吴自玉.,冼鼎昌.,Wu, ZY.,Xian, DC.,Natoli, CR.,...&Mottana, A.(2001).Symmetry dependence of x-ray absorption near-edge structure at the metal K edge of 3d transition metal compounds.APPLIED PHYSICS LETTERS,79(12),1918-1920.
吴自玉,et al."Symmetry dependence of x-ray absorption near-edge structure at the metal K edge of 3d transition metal compounds".APPLIED PHYSICS LETTERS 79.12(2001):1918-1920.