ALL peaks within this element should have +/- 0.2 eV the same FWHM.Ģ. One of the basis of adequate interpretation of changes introduced by any type of modification is i dentification of peaks in unmodified sample. From a reference sample with just one type of N, O or metal, for example, analyzed at your particular instrument it is easy to find what it the adequate width for particular line of the element. natural width of incident X-ray line, thermal broadening, pass energy of the analyzer, lifetime of the electron hole, etc. Fundamental processes contributing into width of the peak used for curve fitting N 1s, in this case, are the same for all peaks used, i.e. This type of curve fit is exactly why there is so much reservations against use of curve fitting of spectra for quantitative evaluations of changes in chemistries.Īnd still itt is very easy to do an accurate reproducible curve fit if you remember a few things.ġ. And, my “intelligent” guess that authors make conclusion on significant decrease of species contributing to binding energy of peak NII from 800 to 900C. And peak NII becomes three times more narrow then in unpyrolyzed sample. So why there is no peak NIII in unpyrolyzed sample? If one makes peak NII in unpyrolyzed sample of adequate width (being the same as in sample at 800 C), then a third peak NIII must be created to complete a curve fit in the unpyrolyzed sample as well.Īt temperature 900 peak NI becomes twice as wide as it is in unpyrolyzed sample. Curve fit of this spectrum by itself meets all necessary requiremenets of a good curve-fit in which main three peaks are of approximately the same FWHM.
Peaks NIII and NIV is added to complete a curve fit. Suddenly peak NII is twice more narrow then it is in unpyrolyzed sample. Peak NI is at the same position of Binding energy and has the same approximate width.
Heat treatment of sample at 800C introduces changes which are obvious from the spectral shape. The first sample is unpyrolyzed sample (unmodified) which is used as a reference. Peak NI is of adequate width for N 1s spectral line. Why, suddenly, peak NII is twice as wide as peak NI? Three N 1s spectra for three samples (unmodified and heated at two different temperatures) are analyzed. Let’s look at one example from the literature. And why spectra on the right represent the “correct” way of curve fitting? What’s wrong with set of spectra shown on the left. So every time I give presentation, which show curve fitting results to people who are not doing it for living, I am talking about physical reasons behind Gaussian-Lorentzian shape of peaks, fundamental limits contributing to FWHM and generals rules of accurate reproducible curve fitting.Īnd the second reason is that even though we all know the rules behind good practices of curve fitting scientific literature is filled with poorly fitted spectra and, therefore, incorrectly interpreted XPS data. Their reaction is that curve fitting is meaningless as we can curve fit any particular spectrum with infinite number of combinations of peaks of different widths and shapes with the same goodness of fit. Run this for building the pypi package and uploading it.Why talk about something so well known to the surface analysis community as curve fitting high resolution XPS spectra? Two reasons.įirst is the skepticism I am running into every time I am showing curve fits of spectra to non-surface analysis communities of scientists. A relation to the same parameter of another peak can be expressed by using their label (see screenshot below).Įxporting the data or the plot is not yet supported. After this, you can constrain the peak values in the bottommost three entries: They accept input either like max where min and max are minimum and maximum values for the corresponding parameter, or like expression which can be a simple arithmetic expression or just a fixed value.
When a region is selected, you can add peaks by clicking "+" next to "Peaks" and drawing them by dragging from the peak maximum downwards inside the selected region. In the fitting tab, you can first add one or more regions by clicking "+" next to "Regions", then dragging across the Plot View. The rightmost icon in the top toolbar lets you select elements whose peak positions should be displayed (see screenshot). When the "Spectra" tab is selected, you can choose the spectra to view by selecting them, right clicking and clicking "Plot selected spectra".
#Xps peak icon software#
txt files from the EIS Omicron software can be parsed.
#Xps peak icon plus#
You can import spectra by clicking the plus icon in the main toolbar. Then, you need PyGObject eiter from or through MSYS ( ).
#Xps peak icon install#
However, you can try to install PyGObject manually and get the xpl package through pip.įirst, you need Python 3.5 (other 3.x will probably work, not tested) from or Anaconda or whatever. I have not yet succeeded in building a windows.
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