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Figure 1
Three models of the absorption spectral change for different damage processes upon X-ray irradiation. (a) The applied X-ray irradiation does not change the near-edge X-ray absorption fine-structure (NEXAFS) spectrum: the pre-edge Apr, the post-edge Apst and the peak Apk optical densities do not change with the dose applied. (b) The peak Apk, corresponding to a particular molecular bond or functional group, decays due to the irradiation applied, while Apr and Apst are unchanged. (c) Irradiation affects the whole NEXAFS spectrum: the Apr value decays due to changed contributions from different elements, the peak value Apk decays due to X-ray induced chemical reactions and the post-edge Apst decays due to removal of atoms from the X-ray probe volume. The black curve is the initial spectrum, the red dashed curve is the result of irradiation, the black dashed curve is an extrapolation of the pre-edge signal, while the change in Apst relative to the extrapolated Apr value indicates the amount of that element.

Journal logoJOURNAL OF
SYNCHROTRON
RADIATION
ISSN: 1600-5775
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