NEXAFS measurements at the oxygen K-edge have been carried out on a variety of crystalline oxide samples to examine the effects of differences in local coordination environment of oxygen on near-edge structure. All spectra display an intense white line at about 543 eV and a strong shape resonance about 20 eV above the edge. The white line shifts to higher energies with increasing oxygen coordination number, although differences in nearest-neighbor type can affect this correlation. In addition, the Ca and transition-metal containing oxides display features 6-10 eV below and 6-9 eV above the white line. The intensities of these features vary inversely with the number of 3d-electrons but their energies are independent of cation oxidation state. Large changes in coordination number and geometry affect edge structure less than variations in types of nearestneighbor cations. The inverse distance-energy relationship is poorly obeyed in these compounds when oxygencation bond lengths are compared with the position of the strongest shape resonance for a given structure type. The near-edge structure is qualitatively interpreted using the results of recent Xα multiple scattered-wave calculations.
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Brown et al. (1986) studied this question.