The unit of atom scattering factor

[einstein1921]

Hi,
I read in some papers which say the unit of atom scattering factor is e/atom.
what is the meaning of that?
thank you!

 

[M Quack]

Assuming that you are talking about the scattering factor for x-rays: X-rays get scattered almost exclusively by electrons, so it is natural to use electrons as unit of scattering.
You then calculate the scattering of a single, free electron. As most electrons are centered around atoms, you then multiply with the number of electrons/atom, and the number (or density) of atoms. At large scattering angles you have to take the spatial distribution of electrons around the nucleus into account, this gives you the form factor, for diffraction you need to consider the position of the atoms, ...