Curve Fit Command
Curve Fitting allows you to superimpose Gaussian, Lorentzian, or Asymmetric
Gaussian-Lorentzian peak shapes on data from an XPS multiplex region. The
parameters of these peaks are adjusted until the resulting summation of the peaks
(the artificial, or synthetic curve) best approximates the experimental data. In
this way, one can derive the individual peaks that make up a given data set
and characterize the chemical state of the data.
Curve fitting can be performed independently for each region of a multiplex.
Results can be displayed on the graph of the curve fit region and copied to the
clipboard for use in other applications.
Curve fitting is inherently complex. If you are not familiar with the
theoretical and applied aspects of curve fitting as it applies to XPS data, you may
wish to consult the various references available.
Although you can only curve-fit a multiplex region, you can curve fit data
from XPS surveys and depth profiles by converting this data to multiplexes. See
the following for more information:
Creating a Multiplex From a Survey
Creating a Multiplex from a Depth Profile
General Curve Fitting Procedure
Following is a brief description of the steps involved in curve fitting:
- Prepare your data for curve fitting. Any data massage and transformation
functions must be done prior to curve fitting.
- Select a baseline for the data, and subtract the background.
- Select the band type, default limits, and maximum number of iterations for the
curve fit.
- Add bands (peaks) that best describe the inherent peaks whose summation will
result in the closest match to the experimental data.
- Adjust the band parameters to obtain a close fit. In essence, you are now
manually curve fitting the data and using visual cues to determine the goodness
of fit.
- Instruct the computer to perform a curve fit, thereby optimizing the
parameters of each band for the closest fit.
- Analyze the results and modify the parameters of the individual bands, limits,
locking, and iterations, if necessary.
Preparing Data for Curve Fitting
Additional Curve Fitting Topics