Analytical Applications of XPS

For low atomic weight elements (Z 30), energy peaks are observable corresponding to the K and L shells (the s and p electrons). For elements with atomic numbers between 35 and 70, the d electrons result in peaks in the XPS spectrum. For elements with atomic numbers greater than 70, 

Quantitative analysis by XPS can be used to determine the relative concentrations of components of a sample. Either peak area or peak height sensitivity factors can be used, but the peak area method is preferred. 

For a homogeneous sample (one that is homogeneous in the analysis volume), the following equation can be written for the intensity of a given spectral peak  

I is the intensity (photoelectrons/s) n is the number of atoms of the element/cm sample /is the X-ray flux (photons/s cm ) 

0 is the angular efficiency factor based on the angle between the photon path and detected electron y is the efficiency of production of primary photoelectrons X is the mean free path of the photoelectrons in the sample (cm) 

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D. Briggs. Analytical Applications of XPS. In C.R. Brundle and A.D. Baker, editors. Electron Spectroscopy Theory, Techniques and Applications, Volume 3. Academic Press, New York, 1979. 

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