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#Free xps peak fitting free

When the Shirley-Sherwood background in employed, the step on the background is shared between the two main features. It corresponds to a Si 2 pspectrum from a silicon substrate (peak on the right) and an oxide layer (peak on the left). The figure below illustrates the difference between the Shirley-Sherwood and the SVSC backgrounds. In addition, the quality of the fits is always better.

It also permits the use of background parameters obtained from other data. The SVSC method allows for assigning different background intensities to the various peaks. This makes complete sense from the physics point of view since the background intensity is not necessarily the same for all the chemical species present in the spectrum. Instead of assessing the background employing the whole spectrum (between the two chosen points), the SVSC method assign a background to one or various peaks.

in this way, the fit becomes much less dependent on the operator.

the operator does not require choosing the two points at each side of the spectrum to define the background and,.

The SVSC-background is a variant of the Shirley-Sherwood background with great advantages since The active method is implemented in AAnalyzer® and is actually easier to employ than the static or traditional method (also implemented in AAnalyzer® for the sake of completeness). The active method always provides better fits. For spoilers, the area calculated with the static method for the example of the figure below underestimates the area by 6% (compare (d) with (b)). The active method has many important advantages (and no disadvantages) over the static method. In contrast, under the static method, the background remains the same between iterations. By comparing Figures (a) and (b), it is possible to appreciate the evolution or the background shape as the fitting optimization process progresses under the active method. This is illustrated in the following figure, which shows different fits of a Ti 2 p spectrum. In contrast, under the traditional or static method, the background is assessed prior to peak fitting. Under the active-background method the shape and intensity of the background is defined during peak-fitting. This method provides a fast and efficient simultaneous fit.įit all ? – The fourth fitting option fits all parameters simultaneously of all files, as with the third option however, it provides a more precise optimized value for each parameter. The center and width of the peaks are fitted to the same values for all the data however, it allows for different peak areas. Likewise, each file will have its own set of fitting parameter values.įit all – The third fitting option fits all “free” parameters (parameters in red font) of all files simultaneously.

#Free xps peak fitting free

Each file will have its own set of fitting parameter values.įit 1/1 ? – The second fitting option also fits all free parameters for all files, one file by one, in a sequential manner however, it provides more precise parameter values.

To begin the fitting process, press any of the fitting buttons located on the upper right corner of the window under the “data and fits plot” tab.įit 1/1 – The first fitting option fits all free parameters for all files, one file by one, in a sequential manner. Examples of codes for all possible variables are found under the miscellaneous tab in the right side of the window. Specify the name of the cell you wish your value to be correlated to, in the space next to “correlated”. For example, to make reference to the Gaussian cell of the first peak, input “g0” -g- for Gaussian, and -0- for row #0. To make reference to a different cell, take the first letter of the name of the column, and match it with its corresponding row number. This option will “fix” the value of the cell to the value of a different cell. On the other hand, the “correlated” option does a similar function to the “fix” function. The “limited” option does a similar function to the “free” function however you must specify the limits in which AAnalyzer must optimize the value. You may choose your values to be “fixed” or “free” by selecting the corresponding button near the lower left corner of the “Fitting Parameters” tab. The black values are “fixed” these values will not change during a fit unless the user changes them. The red font means that the values in these cells are “free” these values will be modified by AAnalyzer when performing a fit in order to find an optimum value. You may notice that some of the values in the “Fitting Parameters” tab are shown in red and others in black.