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{{Unreferenced stub|auto=yes|date=December 2009}}
'''Gas electron diffraction''' (GED) is one of the applications of [[electron diffraction]] techniques. The target of this method is the determination of the structure of [[gaseous molecules]] i.e. the [[Molecular geometry|geometrical arrangement of the atoms]] from which a molecule is built up.
Diffraction occurs because the [[wavelength]] of electrons accelerated by a potential of a few thousand volts is of the same order of magnitude as internuclear distances in molecules. The principle is the same as that of other electron diffraction methods such as [[Low-energy electron diffraction|LEED]] and [[RHEED]], but the obtainable diffraction pattern is considerably weaker than those of LEED and RHEED because the density of the target is about one thousand times smaller. Since the orientation of the target molecules relative to the electron beams is random, the internuclear distance information obtained is one-dimensional. Thus only relatively simple molecules can be completely structurally characterized by electron diffraction in the gas phase. It is possible to combine information obtained from other sources, such as [[rotational spectroscopy|rotational spectra]], NMR spectroscopy or high-quality quantum-mechanical calculations with electron diffraction data, if the latter are not sufficient to determine the molecule's structure completely.
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