Determination of the position of V4+ as minor component in XPS spectra by difference spectra

Difference spectra are used to determine the positions of minor components in XPS spectra without additional samples and without concerning the complication of the background. The requirements for obtaining accurate difference spectra are discussed. The displacement between V4+ 2p3/2, a minor component in V2O5 XPS spectra, and V5+ 2p3/2, is determined to be 2.0 eV.