Charged Particle-Surface Interactions and Spectroscopies

Abstract

In a set of lectures, we treat the interaction of a charged particle with a solid when the particle travels outside of the solid. This situation is relevant to a number of experimental techniques used to investigate solid surfaces, such as UPS and XPS (ultraviolet and X-ray photoelectron spectroscopy), EELS (electron energy loss spectroscopy), several ion spectroscopies, electron tunneling, etc. There is a vast body of old and recent literature on the classical and quantum behavior of a charge near a solid surface in the different energy regimes from the static to the fast-particle cases. Some aspects of this work will be reviewed in the present School. Irrespective of the nature of the charge (electron, positron, proton, complex ion, etc.), its interaction with the solid always includes and, at large distances, is dominated by the ubiquitous “image potential”. A description of the image potential, particularly of its quantum manifestation in EELS, is the main subject of the present lectures. The single unifying concept of an effective dielectric function will be introduced and used throughout the lectures to construct the static and dynamic potential of the charge to which the solid responds.