Scattering by a bound electron

Generally speaking, it can be shown that the total interrsity scattered by a bormd electron is eqital to the cohererrt irrtensity scattered by a fiee electron, as given by the Thomson formitla. This resirlt can be expressed by the relation  

Since the volume dV contains the charge pdV, it scatters an amplitude equal to the one scattered by one electron multiplied by pdV. If we consider coherent scattering, the waves scattered by each elementary volume dV interfere, because they have the same wavelength. The coherent amplitude scattered by the botmd electron is therefore given by the sum of the amplitudes scattered by each volume elemerrt dV and hence  

The paA length between point O and the volume element dV is equal to S = r.(S-Sq) and the phase difference ) is expressed as  

We have already mentioned that the vector (S - Sq is the scattering vector s 

The following term is referred to as the electron cloud s scattering factor  

---