A new asymmetric Pseudo-Voigt function for more efficient fitting of XPS lines
Schmid M, Steinrück HP, Gottfried JM (2014)
Publication Type: Journal article, Original article
Publication year: 2014
Journal
Original Authors: Schmid M., Steinrück H.-P., Gottfried J.M.
Publisher: Wiley-Blackwell
DOI: 10.1002/sia.5521
Abstract
Asymmetric peak profiles for the application in spectroscopy can be obtained in a simple way by substituting the usually constant full width at half maximum parameter in Pseudo-Voigt functions with an energy-dependent expression, for instance of sigmoidal shape. While this approach has been successfully applied to vibrational spectra, we find that the resulting curves are less suitable for least-squares fits of X-ray photoelectron spectroscopy (XPS) data. However, if one additionally allows a variable displacement of the sigmoidal step relative to the peak, excellent fitting results can be obtained. We demonstrate the applicability of our extended approach on several inherently asymmetric XPS lines, i.e. the C 1s signal of graphite and CH/Pd(100), the 3d-3d doublet of palladium, and the 4f-4f doublet of platinum. Comparison of the corresponding fit results with the results obtained by the application of more elaborate, theory-based line profiles (Doniach-Šunjić and Mahan functions) shows that the modified Pseudo-Voigt function gives practically identical results in terms of peak shape and area, while requiring much less computational effort since no convolution procedures are required for its calculation. Thus, this function is most suitable for application in one of the following situations: (i) the peak shape of a given signal is known but cannot be calculated with ease, and (ii) the theoretical peak shape is not (yet) known, however, one wants to perform a first quantitative screening of the data at issue. © 2014 John Wiley & Sons, Ltd.
Authors with CRIS profile
Martin Schmid
Lehrstuhl für Physikalische Chemie II
Hans-Peter Steinrück
Lehrstuhl für Physikalische Chemie II
Additional Organisation(s)
Involved external institutions
Germany (DE)How to cite
APA:
Schmid, M., Steinrück, H.-P., & Gottfried, J.M. (2014). A new asymmetric Pseudo-Voigt function for more efficient fitting of XPS lines. Surface and Interface Analysis. https://dx.doi.org/10.1002/sia.5521
MLA:
Schmid, Martin, Hans-Peter Steinrück, and J. Michael Gottfried. "A new asymmetric Pseudo-Voigt function for more efficient fitting of XPS lines." Surface and Interface Analysis (2014).
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