ABSTRACT
Atomistic pictures of silica surfaces are often based on theoretical considerations rather than solid experimental results. The preparation of the clean surface of silica is not a trivial task. Clean surfaces prepared by sputtering in ultrahigh vacuum (UHV) often suffer from the compositional non-stoichiometry. LEED is one of the mostly used techniques for studying crystalline and well-ordered surfaces and interfaces. The principles of electron diffraction are intimately connected to the wave-like nature of elementary particles, first introduced by Louis de Broglie in 1924 and then confirmed experimentally by Davisson and Germer in 1927. The response of the solid sample surface to the external electric field of the probe electron can be described in terms of the surface dielectric response with frequency of the external electric field.
