SKα, SKβ and FeKβ valence related wavelength changes are large enough to be measured with microprobe spectrometers. The relative difference between S2- and S6+ is measured as 1.27 eV for the SKα line and 1.66 eV for the SKβ line. This SKα and SKβ peak shift is function of the valence. Accurate microprobe measurement of the peak shift allows the determination of the sulfur valence in a microarea. The relative difference between Fe2+ and Fe3+ for the FeKβ line is 0.94 eV. Considering the achieved accuracy of measurements, this peak can only be used for an approximate determination of the iron valence in a microarea.
Kucha, H.; Wouters, R.; and Arkens, O.
"Determination of Sulfur and Iron Valence by Microprobe,"
Scanning Microscopy: Vol. 3
, Article 11.
Available at: https://digitalcommons.usu.edu/microscopy/vol3/iss1/11