Atomic Excitation Exploited By Energetic-Beam Characterization Methods
Published Online: 12 OCT 2012
Copyright © 2003 by John Wiley & Sons, Inc. All rights reserved.
Characterization of Materials
How to Cite
Jeynes, C. and Grime, G. W. 2012. Atomic Excitation Exploited By Energetic-Beam Characterization Methods. Characterization of Materials. 1–17.
- Published Online: 12 OCT 2012
Many disparate methods of compositional analysis of materials are underpinned by the same fundamental atomic processes: the excitation of the electronic system of the atoms followed by its subsequent relaxation. These methods include the electron spectroscopies (XPS, AES) used for surface studies, the electron microscopies used for elemental and structural characterization (SEM using EDS and WDX; TEM using EELS), and the X-ray methods (XRF, XAS) and ion beam analysis (PIXE) used for elemental and chemical characterization. All rely on measuring the characteristic energy absorbed or emitted by the unknown target atom when its electronic system is excited by ionization due to charged particles or electromagnetic radiation. This excitation is defined by the energy levels of the atomic electrons, determined primarily by the atomic number of the atom. (Atoms can also be excited without ionization, as in optical and infrared spectroscopy: this is outside the scope of this article.)
The theoretical description of the electronic structure of atoms is a major intellectual triumph of the twentieth century and this body of knowledge is exploited in the theoretical description of each of these methods, but the treatment of any particular method is usually presented by specialists in that method in isolation from all others. In this article we present a brief synthetic overview of materials analysis using atomic excitation, highlighting those features and physical concepts that underpin all these apparently disparate analysis methods. We hope to encourage modern analysts to appreciate the truly complementary nature of the powerful methods at their disposal.