Ferrous (Fe 2+ ) and ferric (Fe 3+ ) compounds were investigated by XPS to determine the usefulness of calculated multiplet peaks to fit high-resolution iron 2p 3/2 spectra from high-spin compounds. The multiplets were found to fit most spectra well, particularly when contributions attributed to surface peaks and shake-up satellites were included. This information was useful for fitting of the complex Fe 2p 3/2 spectra for Fe 3 O 4 where both Fe 2+ and Fe 3+ species are present. It was found that as the ionic bond character of the iron -ligand bond increased, the binding energy associated with either the ferrous or ferric 2p 3/2 photoelectron peak also increased. This was determined to be due to the decrease in shielding of the iron cation by the more increasingly electronegative ligands. It was also observed that the difference in energy between a high-spin iron 2p 3/2 peak and its corresponding shake-up satellite peak increased as the electronegativity of the ligand increased. The extrinsic loss spectra for ion oxides are also reported; these are as characteristic of each species as are the photoelectron peaks.

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Photoelectron spectra of a number of chromium oxides and other compounds were studied under high spectral resolution conditions chosen to reduce the possibility of differential charging. Some of the suite of Cr(III) compounds chosen for study produced Cr 2p spectra containing fine structure that could be identified with multiplet splitting. The splitting patterns produced were similar for all trivalent binary and ternary oxides and sulphides whose patterns closely reproduced the splitting predicted for the Cr(III) free ion by Gupta and Sen. The fine structure observed for compounds such as chromium (III) chloride had a distinctly different pattern. A number of other chromium (III) compounds were studied that did not exhibit the fine structure described above; nonetheless, well-defined line shapes and reproducible peak centroids were obtained by fitting protocols. The use of such information to determine surface chemistry on chromated steels is described, based on the spectral knowledge of chromium (III) oxides and hydroxides and the chromium (VI) oxide systems.

Application of target factor analysis and linear least squares fitting to extracting chemical information from Auger depth profiles of a Mo/Si thin multilayer system Shape information from a critical point analysis of calculated electron density maps: application to DNAdrug systems AIP Conf.

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