Elastic single scattered intensity

For the sake of simplicity we now consider electrons as stationary points and disregard the dependence of the scattered intensity on the scattering angle. Each electron then interacts with the incident x-ray wave producing a spherical elastically scattered wave as shown in Figure 2.20. Thus, the scattering of x-rays by a single electron yields an identical scattered intensity in every direction. 

The intensity I of light scattered from an incident unpolarized beam of wavelength X and incident intensity Io by a single small particle of diameter d and refractive index n by the elastic, coherent Rayleigh process is given by... 

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