Chemical Science and Technology Laboratory
The Surface and Microanalysis Science Division

On-Line Evaluation of XPS-STD Analyses

This page evaluates the binding energies and intensities of peaks from a user's analysis of the XPS-STD. This page and its graphical capabilities are designed to be used with a browser that supports Java^TM 1.1^*.

For binding energies, the larger peak in the doublet spectra is evaluated, as are the peaks in the singlet spectra. For peak intensities, we determine the ratio of the area of the larger peak in the doublet to the total peak area in the spectrum. These ratios are compared with the known area ratios for each doublet in the design. For the evaluation of peak intensities in the singlet spectra, we determine the ratio of the peak area of one of the two singlets at a particular noise level to the area of both singlets in the design.

Once you have analyzed the XPS-STD, paste your data in the appropriate box below. Make sure you enter the number of the first spectral data set you analyzed among the 220 sets. Then, enter the number of data sets you analyzed. The data sets must be in consecutive order, e.g., sets 1,2,3,4,5 or 2,3,4,5,6 but not 1,3,4,5,6. Next, identify your curve-fitting approach from the pull-down menu. Finally, press Calculate. For complete instructions on entering results, see the Instructions Page.

Once you enter your curve-fitting results, the bias and random error for each of the 22 spectra (18 doublets and 4 singlets) are calculated. Bias is the average deviation from the true value for either the peak binding energy or the peak intensity ratio as described above. Random error is the root-mean-square deviation. Choose to view your evaluation as either graphs or tables, under View Output: below. Under Analysis of:, choose the evaluation of either Binding Energies or Intensities. Finally, choose Bias or Random Error under Graph Display of: below.

The Graphs are box plots for comparing your results with the range of results from the Study Group that used the same curve-fitting approach. The boxes enclose the inter-quartile range, the center line in each box is the median, and end caps are the 5th and 95th percentiles.

The Tables allow you to compare the actual error values for your binding energies or peak intensities - in black - with statistics for the Study Group - in blue - (see Key). For example, bias and random error in binding energies for the larger peak in the doublet are shown in the two 3-row by 3-column tables labeled Low Noise and High Noise for Doublets, or a 2-column table for Singlets. Peak separation increases from col. 1 to col. 3. Relative Peak Height varies from row 1 to row 3, as indicated. To review the conditions for peak separation, peak height and Poisson noise, see XPS-STD Design. For further information on the results for the study group, see Pilot Study.

Finally, please submit your error values so that we can expand our database. We do not associate error data with individual users. So, your data will remain anonymous in our database.

Thank you for using Interactive Standard Test Data. If you have any questions or comments, please contact Joe Conny (301-975-3932, fax 301-216-1134, joseph.conny@nist.gov).

^*The identification of commercial products is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the products identified are necessarily the best available for the purpose.