Characterization of the ethyl xanthate adsorption layer on galena (PbS) by synchrotron radiation excited photoelectron spectroscopy

Abstract Utilization of synchrotron radiation excitation in photoelectron spectroscopy (SR-XPS) of solid surfaces provides a significant improvement in surface sensitivity of the method. It has recently been shown that almost an order of magnitude increase in relative intensity of the sulfur 2p signal from the very first atomic layer of a sulfide can be achieved by using SR instead of conventional AlKα or MgKα X-rays for photoelectron excitation. In this work, SR-XPS was applied to characterize the xanthate layer adsorbed on galena in 10 −4 M potassium ethyl xanthate solution (pH 9.2) in equilibrium with air. Chemisorption of xanthate radicals rather than formation of bulk lead ethyl xanthate was observed. Prolonged irradiation of the sample by the SR beam was observed to decompose the adsorption layer. Means to avoid radiation damage during the SR-XPS measurement is discussed.