X-ray Photoelectron Spectroscopy (XPS) Reference Pages

Mg 2p and 2p-KLL Auger Paramenter Values [1].

Notes:
O 1s for MgO is at 530.6 eV +/- 0.9 eV (7 references).

Reference:
[1] C.D. Wagner, A.V. Naumkin, A. Kraut-Vass, J.W. Allison, C.J. Powell, J.R.Jr. Rumble, NIST Standard Reference Database 20, Version 3.4 (web version) (http:/srdata.nist.gov/xps/) 2003.

The CasaXPS/Kratos R.S.F. value (of 0.6) for the Mg KLL Auger line tends to significantly overestimate the amount of magnesium present compared to the quantitative values found from the Mg 2p and Mg 2s lines. A new R.S.F. value calculated from standard samples (magnesium metal and magnesium oxide) has been developed for use on samples where the Mg 2p or Mg 2s peaks are either too small or overlapped with other species. A value of 4.3 +/- 0.3 was found to work quite well. Use a background encompassing the main peak of the Mg KLL line extending from approximately 315 eV to 298-300 eV. Interference from strong C 1s loss structure can be mitigated by shifting the lower binding energy background endpoint to a slightly higher binding energy.

Mg KLL Auger R.S.F. = 4.3 +/- 0.3

Magnesium reference spectra used for this calculation and showing the full Mg Auger peak-set are presented in the link.

When analyzing a magnesium rich sample using monochromatic Al K(alpha) X-rays it may be found that photoelectrons interacting with magnesium in the sample will produce Mg K X-rays. These X-rays can then cause the emission of photoelectrons that will be seen in the spectrum. For example: the Mg K X-ray induced peak for O 1s would be found at a binding energy of ~ 763 eV, as the KE of these photoelectrons would be 1253 eV (hv of Mg K X-rays) - 530 eV (O 1s B.E.) = 723 eV. Thus, they would then be seen as a peak at a binding energy of 1487 (hv 0f Al K(alpha) X-rays) - 723 eV = 763 eV. The C 1s Mg X-ray induced peak would be at a binding energy of ~517 eV.

Also of note for spectra of samples containing large amounts of magnesium: Mg Auger structure can be found at ~242 eV, this peak is not noted in most libraries and may cause confusion during peak assignment.