ELASTIC-SCATTERING CORRECTIONS IN AES AND XPS .3. BEHAVIOR OF ELECTRON-TRANSPORT MEAN FREE-PATH IN SOLIDS FOR KINETIC ENERGIES IN THE RANGE100EV-LESS-THAN-E-LESS-THAN-400EV

Quantitative Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) depend on an accurate knowledge of the correct dep th scale of emission of the signal electrons. This depends on both ine lastic and elastic scattering processes occurring in the specimen unde r analysis. A previous paper showed that the depth scale in AES and XP S is significantly influenced by unexpected structure in the transport mean free path for electrons in high-atomic-number elements over the approximate energy range 100-400 eV. This behaviour is implicit in Mot t cross-sections, which are known to be reliable and have been used in low-energy electron diffraction (for example) for decades. This paper examines the features of electron-atom elastic scattering over the ra nge of energy and atomic number important in XPS and AES analysis. In particular, the third and fourth partial waves, together with Levinson 's theorem are shown to give rise to the structure in the transport me an free path. This is a transport cross-section analogue of the Ramsau er-Townsend effect exhibited at low energies in total elastic scatteri ng cross-sections. (C) 1997 by John Wiley & Sons, Ltd.