How do photons interact with atoms in X-ray diffraction?

[matt_crouch]

How do the photons actually interact with the atoms to make them diffract. is it related to de broglies equation some how?

Also with High energy electron diffraction, are the electrons being diffracted because they are attracted and repelled electrostatically from the nucleus and orbiting electrons?

 

[turin]

I believe that the x-rays excite the inner-most electron shells (or possibly the nucleas, but I think that nuclear excitations require gamma ray energies, and, in fact, this is the original basis for the definition of gamma ray vs. x-ray). Then, the excited shells become temporary (i.e. one-shot) isotropic radiators that can be stimulated by the next ray.

For electrons, the first approximation is that they scatter on the lattice of Coulomb potentials of the nuclei. This scattering can be predominently wave-like in nature if the wavelength is long enough. However, if the wavelength is too long, the electrons cannot pass through for other reasons besides back-scattering.