Mechanisms of Electron-Stimulated Desorption

Abstract

The various phenomena associated with the desorption of neutral and ionic species from surfaces under bombardment by electrons, generally in the 10–300 eV range, are collectively known as ESD (electron-stimulated desorption) or EID (electron-impact desorption). Related effects, for instance, the rearrangement of adsorbates under electron impact or the ejection of weakly bound species by direct momentum transfer from electron des orbed atoms or molecules are also included. The excitation processes and the subsequent evolutions of the substrate-adsorbate systems on excited state potential hypersurfaces are of great intrinsic interest and can illuminate aspects of bonding at surfaces hard to study by other means. ESD also serves as a probe of different binding states, since desorption cross sections and products are sensitive to the details of adsorption. Finally ESD and the closely related photon stimulated desorption (PSD) are of technological importance, for instance in plasma-wall interactions in fusion reactors of the Tokamak type.