A brief review on the use of Auger parameters and Wagner plots (chemical-state plots) in the characterization of surfaces by XPS is presented with particular reference on their applications to barium compounds. Computational (Tinker) and computer graphic (Molden) programs, available free of charge from the web permit, respectively, the calculation of Auger parameter shifts at the electrostatical level of theory and the graphical display of the atomic structures involved. An application of these methods is reported for a BaCl(2) crystal, considering the Auger parameter shift of Ba(2+) ions in different localizations. The effects of distant cations and anions from the ion with the core hole may be easily investigated together with the effect of decreasing the coordination number of an ion because of its localization at the surface of the material. For such an ion, the effect of adsorbed molecules (e.g. water and hydrogen sulfide molecules) on the Auger parameter shift can also be calculated. The initial- and final-state effects determine the localization of a barium compound in the Wagner plot which is a very useful tool in the chemical-state analysis. (C) 2009 Elsevier B.V. All rights reserved.
Auger parameters and Wagner plots / Satta, Mauro; Moretti, Giuliano. - In: JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA. - ISSN 0368-2048. - 178:C(2010), pp. 123-127. [10.1016/j.elspec.2009.07.008]
Auger parameters and Wagner plots
SATTA, Mauro;MORETTI, GIULIANO
2010
Abstract
A brief review on the use of Auger parameters and Wagner plots (chemical-state plots) in the characterization of surfaces by XPS is presented with particular reference on their applications to barium compounds. Computational (Tinker) and computer graphic (Molden) programs, available free of charge from the web permit, respectively, the calculation of Auger parameter shifts at the electrostatical level of theory and the graphical display of the atomic structures involved. An application of these methods is reported for a BaCl(2) crystal, considering the Auger parameter shift of Ba(2+) ions in different localizations. The effects of distant cations and anions from the ion with the core hole may be easily investigated together with the effect of decreasing the coordination number of an ion because of its localization at the surface of the material. For such an ion, the effect of adsorbed molecules (e.g. water and hydrogen sulfide molecules) on the Auger parameter shift can also be calculated. The initial- and final-state effects determine the localization of a barium compound in the Wagner plot which is a very useful tool in the chemical-state analysis. (C) 2009 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.