QUANTITATIVE XPS MEASUREMENTS OF SOME OXIDES, SULFIDES AND COMPLEX MINERALS

A number of binary oxides, sulphide compounds and complex minerals hav e been analysed by x-ray photoelectron spectroscopy to give the relati ve intensities of major photoelectron lines, Where possible, compound surfaces were prepared by fracturing in vacuo or in inert gas to avoid contamination. Alternatively, some of these compounds have undergone a mild thermal treatment in vacuo to remove much of the surface contam ination which normally affects such intensity measurements, The experi mental line intensity ratios were corrected only by their particular p hotoelectron cross-section and inelastic mean free paths, For most oxi des and complex minerals studied, good agreement is obtained with the expected stoichiometry, particularly when using photoelectron lines of higher kinetic energy, This tends to support the use of a simple back ground approximation when measuring specifically with those oxides inv olving non-transition elements, The sulphides studied mostly involved transition metals; agreement between calculated and actual stoichiomet ry was only modest, Some differences in measured surface stoichiometry occurred as a result of the ambient conditions within which the fract ure was made; fracture in vacuo produced a different S/M ratio than di d fracture in an inert pas environment.