From the mathematical formula, $$ \Delta \lambda = \dfrac{\mathbf{h}(1 – \cos \phi)}{m\mathtt{c}}$$ that when $\phi = 0$° shifting of wavelength wouldn't take place. But what is the physical reason?
Let there be a stationary electron and X – ray is struck on it . What is the physical reason that the wave will not have its wavelength shifted when $\phi = 0^\circ$? Scattering angle is determined when the scattered ray has made that angle after already passing the electron. So, does it mean when the ray does not interact with the particle, the scattering angle becomes zero??
Best Answer
Its actually somehow momentum conservation I think: By noticing that $\Phi = 0^\circ$ you also can imagine, that the photones momentum did not change, which results in having no interaction and so on the other hand no change of the wavelength.