ISO 19830:2015

INTERNATIONAL ISO
STANDARD 19830
First edition
2015-11-15
Surface chemical analysis — Electron
spectroscopies — Minimum reporting
requirements for peak fitting in X-ray
photoelectron spectroscopy
Analyse chimique des surfaces — Spectroscopie d’électrons —
Exigences minimales pour le rapport d’ajustement de pic en
spectroscopie de photoélectrons X
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Terms and definitions . 1
3 Symbols and abbreviated terms . 2
3.1 Abbreviated terms . 2
3.2 Symbols . 2
4 Reporting of relevant data acquisition parameters . 3
4.1 General . 3
4.2 Spectrometer . 3
4.3 Instrument resolution. 3
4.4 Detector . 3
4.5 X-ray source . 4
4.6 Element identity . 4
4.7 Energy range in the spectrum . 4
4.8 Energy step size in spectrum . 4
4.9 Charge compensation . 4
5 Reporting of single-spectrum peak-fitting parameters . 5
5.1 General . 5
5.2 Background range . 5
5.3 Background integration range . 5
5.4 Background type . 5
5.5 Application of a fitted background . 5
5.6 Setting the peak parameters . 6
5.7 Peak area and peak height . 6
5.8 Peak area and peak height ratios . 6
5.9 Full width at half maximum . 6
5.10 Peak shape . 6
5.11 Peak asymmetry parameters . 7
5.12 The peak-fitting process . 7
5.13 Residual spectrum . 7
6 Multi-spectrum peak fitting . 7
6.1 General . 7
6.2 Peak fitting methods for multi-spectrum data sets . 7
6.3 Propagation of constraints . 8
6.4 Background propagation . 8
7 Satellite subtraction . 9
8 Doublet subtraction . 9
9 Spectrum deconvolution .10
10 Fit quality and uncertainties .10
10.1 General .10
10.2 Fit quality .10
10.3 Uncertainty in the reported binding energies .10
10.4 Uncertainty in the peak areas .10
Annex A (informative) Example of reporting peak fitting .11
Annex B (informative) Reporting peak fitting for multi-level data sets .14
Annex C (informative) Template for reporting peak fitting parameters .17
Annex D (informative) Statistical methods .19
Bibliography .22
iv © ISO 2015 – All rights reserved

Foreword
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The committee responsible for this document is ISO/TC 201, Surface chemical analysis, Subcommittee
SC 7, Electron spectroscopies.
Introduction
X-ray photoelectron spectra produced from the surfaces of many materials are complex and frequently
consist of overlapping or unresolved peaks. The lack of resolution can be due to instrumental
parameters, the X-ray line width, the natural line width of the transition, or a contribution from all of
these. It is frequently necessary, therefore, to use a mathematical procedure to fit some or all of the
peaks in XPS spectra in order to establish the position and intensity of each of the component peaks
contained within each peak envelope. This is often the first step in the identification of the chemical
states which give rise to the overall peak envelope and the quantification of each chemical state present.
The analyst must therefore have confidence in both the position (to establish the chemical state) and
the peak area (to allow accurate quantification) of each peak reported following peak fitting.
The mathematical procedure applies model peak and background shapes, the defining parameters
of which are varied in order to obtain the optimum fit to the experimental data. Most commonly, the
model peak shapes are some combination of Gaussian and Lorentzian functions.
Many of the parameters that should be reported following peak fitting are those that define these
curves. Other factors are those which are selected by the analyst to ensure that the peak-fitting process
results in a chemically meaningful description of the peak envelope or to minimize the time taken for
the fitting process. These include parameters that the analyst
— chooses to fix at a constant value during the fitting process,
— defines as a range of values over which the parameter can vary during the fitting process, and
— mathematically links the value of a parameter to that of another parameter
Peak fitting is a purely mathematical process fro
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