In 1922, Arthur Compton described the scattering of X-rays on graphite as interaction process between light-particles and electrons.
However as will be demonstrated in the following, the difference measured by Compton between the wavelength λ2 of the scattered and the wavelength λ1 of the incoming radiation – dependent on the scattering angle ϑ –
(λC ... Compton wavelength of the electron)
can be derived just as well under the assumption that the scattering process is a pure wave phenomenon; Yet not in a quantum-theoretic way – not any of the concepts originating from mechanics, as energy, momentum, mass etc. will be needed.