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Electron Refraction of Amorphous Nanospheres

Published online by Cambridge University Press:  02 July 2020

Y.C. Wang ,
T.M. Chou  and
M. Libera
Y.C. Wang
Affiliation:
Stevens Institute of Technology, Hoboken, New Jersey, 07030
T.M. Chou
Affiliation:
Stevens Institute of Technology, Hoboken, New Jersey, 07030
M. Libera
Affiliation:
Stevens Institute of Technology, Hoboken, New Jersey, 07030
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Extract

The phase shift imparted to an incident high-energy electron wave in a TEM is related to the specimen’s electron-refractive properties. These, in turn, are related to the electrostatic potential and, by Fourier transform (1), to the electron scattering factors fei(s) for the various atom species i in the specimen and scattering vectors s. The average refractive index is determined by the mean electrostatic (inner) potential, Φo, and can be modelled as Φo = (C/Ω) Σfei(s0) [equation 1] where C = 47.878 (V-Å2) and the summation runs over all of the atoms in the unit volume Ω (2). Calculated fei(s) data are available from the literature (e.g. 3). These calculations have only been done for neutral atoms and some fully ionized cations and anions. They do not account for electron redistribution due to covalent bonding to which Φo is quite sensitive (4).

This research is making Φo measurements using transmission electron holography. Holograms were collected using a 200keV Philips CM20 FEG TEM equipped with a non-rotatable biprism (5) and a Gatan 794 Multiscan camera.

Type
Electron Crystallography; the Electron Phase Problem
Information
Microscopy and Microanalysis , Volume 3 , Issue S2: Proceedings: Microscopy & Microanalysis '97, Microscopy Society of America 55th Annual Meeting, Microbeam Analysis Society 31st Annual Meeting, Histochemical Society 48th Annual Meeting, Cleveland, Ohio, August 10-14, 1997 , August 1997 , pp. 1055 - 1056
Copyright
Copyright © Microscopy Society of America 1997

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References

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