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

Utilization of synchrotron radiation excitation in photoelectron spectrosco py (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 t he very first atomic layer of a sulfide can be achieved by using SR instead of conventional AlK alpha or MgK alpha X-rays for photoelectron excitation . In this work, SR-XPS was applied to characterize the xanthate layer adsor bed on galena in 10(-4) M potassium ethyl xanthate solution (pH 9.2) in equ ilibrium with air. Chemisorption of xanthate radicals rather than formation of bulk lead ethyl xanthate was observed. Prolonged irradiation of the sam ple by the SR beam was observed to decompose the adsorption layer. Means to avoid radiation damage during the SR-XPS measurement is discussed. (C) 199 9 Elsevier Science B.V. All rights reserved.