Electron energy loss spectroscopy
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In EELS electron energy loss spectroscopy a material is exposed to a beam of electrons with a known (kinetic) energy. Some of the electrons will lose energy in the collision process. Their kinetic energy is analysed and a spectrum constructed. The spectrum contains a.o. information on the vibrational states of the specimen.

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The original article can be found at: http://en.wikipedia.org/wiki/Electron_energy_loss_spectroscopy.
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