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Just to explain this question in a better way just think about the Rutherford's experiment(the alpha particle bombarded on Gold foil) be conducted using a electron gun in place of the Alpha one.. So what will happen when electron is targeted on a gold foil?

Either the atom rather the electrons of Ag atom become excited and therefore emit some sort of waves(if yes,then what kind of waves?), or in return electrons are ejected from the atom along with some waves, or it may be possible that the electron pass by the gold foil without any effect...

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Well, I think, in principle, depending on the energy of electrons, different events can happen, but in the classical experiment electrons will diffract from the spacing within crystal lattice of gold in the foil.

P.S. The experiment is actually very well known in the history of science due to the following reason (quoted from here).

It is interesting to recall that G.P. Thompson, who shared the 1937 Nobel Prize with Davisson for these experiments which proved that electrons are waves, is the son of J.J. Thompson who received the Nobel Prize in 1906 for proving that cathode rays were actually particles - electrons! And the amazing thing is that they were both right.

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  • $\begingroup$ IT may also be possible that electrons strike the atom resulting in emitting of electron present in the atom of Ag and those Ag electron may possibly have K.E. causing observation on wave nature of newly emitted electrons. $\endgroup$ – Siddharth Yadav Jul 21 '14 at 11:35
  • $\begingroup$ ?????????????????????? $\endgroup$ – Siddharth Yadav Jul 21 '14 at 14:33
  • $\begingroup$ So, it was the question? Yes, it possible. But how can you explain a diffraction pattern by this process? $\endgroup$ – Wildcat Jul 21 '14 at 14:51
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Multiple interactions can happen.
First, lets look at the "simple" case of an electron interacting with a single atom. There are three options. (1) the electron does not interact with the (neutral) atom - it misses completely and keeps on going. (2) the electron may interact with the electron cloud of the atom. This may lead to a scattering event, kicking a bound electron into a higher energy level, or knocking it off the atom entirely (generating the secondary electrons used for imaging in an SEM). The atom can then relax, possibly releasing an x-ray or an Auger electron, both of which are used for composition analysis of materials. The incident electron is deflected from the original path because of the scattering event. (3) the electron may interact with the nucleus and undergo Rutherford scattering (yup, same formula applies). The more complex case of an electron impinging on a crystal adds the periodic potential of the crystal. All of the events listed above apply, but in addition the periodic potential allows for diffraction, where the electron scatters off the Bloch waves of the crystal. In a TEM diffraction can be imaged from the transmitted beam, in an SEM it can be imaged from the back-scattered beam (EBSD). So, pretty much everything you mentioned can and does happen. All are used for various measurements in materials science and physics.

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