XPS Study of Iron Phosphate Glasses

X-ray photoelectron spectroscopy (XPS) has been used to characterise the short range structure of iron phosphate glasses. Quantitative Fe 2+ /Fe 3+ ratios determined by decomposing the Fe3p spectra are in good agreement with valence measurements made by Mossbauer spectroscopy. Fe 2+ is preferred when [Fe]/[P] is low, whereas Fe 3+ is preferred when [Fe]/[P] is greater than ∼ 0.4. Increasing [Fe]/[P] decreases the bridging to nonbridging oxygen ratio determined from the OS1 spectra