Bulk phase absorption Subject

Several experimental techniques can be used to study surfaces. X-ray Photoelectron Spectroscopy (XPS), Auger Spectroscopy, X-ray Absorption Spectroscopy, Low Energy Electron Diffraction (LEED), Infra-Red spectroscopy (IR), Raman spectroscopy. Time of Flight Secondary Ionization Mass Spectroscopy (ToF-SIMS), different microscopy techniques, cyclic voltammetry and many other methods have been used to understand the chemical composition and also the reactivity of many sulfide surfaces. However, any analysis using these methodologies are not limited to surface atoms and contributions from the bulk phase are also included. In LEED, for example, in which the incident electrons are elastically backscattered from a surface and subjected to diffraction, the electrons can travel around 5-20 A into the solid. This will make any spectra analysis very difficult and, sometimes, not conclusive. 

The phase relations among the scattered wavelets depend on geometrical factors scattering direction, size, and shape. But the amplitude and phase of the induced dipole moment for a given frequency depend on the material of which the particle js composed. Thus, for a full understanding of scattering und absorption by small particles, we need to know how bulk matter responds to oscillatory electromagnetic fields this is the subject of Chapters 9 and 10. 

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