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Excitation of Dielectric Spheres by Electron Beams

  • P. M. Echenique
Part of the NATO ASI Series book series (NSSB, volume 188)

Abstract

Recent new developments and applications of the scanning transmission microscope(STEM) have stimulated renewed interest in the interaction of high-energy electron beams with small particles and surfaces[1–7]. Usually the classical theory of energy loss has been employed to analyze the experimental energy-loss spectra for planar, spherical or cylindrical geometries [8–14]. A new general approach, based on the self-energy formalism of the many body problem has been presented recently[15]. In this approach, the mean potential energy Σo of the incoming electron, in a state defined by a wave function ψo(r) and energy Eo is written as the average of an effective local potential Veff(r), representing the complex interaction of the incoming electron with the many body target
$${\Sigma_o}=\int{\psi_o^*} (\bar r){V_{eff}}(r){\psi_o}(\bar r)dr$$
(1)
We use atomic units (e2 = h = m) throughout this paper. The real part of Σo gives us the lowering of the energy of the particle due to virtual excitations of the medium, and the imaginary part is directly related to the probability of energy loss due to creation of real excitations. The effective potential is written as a spatial integral of the non local self-energy[16], Σ (r, r’, Eo), which in turn can be expressed in terms of the Green’s function G(r, r’, ω+E0) and the causal screened interaction W(r, r’, ω)[16].

Keywords

Impact Parameter Dipole Contribution Incoming Electron Energy Loss Rate Dielectric Sphere 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Press, New York 1988

Authors and Affiliations

  • P. M. Echenique
    • 1
  1. 1.Departamento de Físcia, Facultad de QuimicasEuskal Herriko UnibertsitateaEuskadiSpain

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