Hello Everybody! I was trying to make some sense from Bernhard Rupp's book page 251.
I will copy the relevant part... When photons travel through a crystal, either of two things can happen: (i) nothing, which happens over 99% of the time; (ii) the electric field vector induces oscillations in all the electrons coherently within* the photon's coherence length* ranging from a few 1000 Angstroms for X-ray emission lines to several microns for modern synchrotron sources. At this point, the photon ceases to exist, and we can imagine that the electrons themselves emanate *virtual waves*, which constructively overlap in certain directions, and interfere destructively in others. The scattered photon then *appears again in some direction*, with the probability of that appearance proportional to the amplitude of the combined, resultant scattered wave in that particular direction.......The sum of all scattering events of independent, single photons then generates the diffraction pattern. I underlined the problematic parts... can anyone shed some light on this ..or point me in the right direction? Thanks in advance
