where l (m) runs over all atom types belonging to w l (w m ). The atomic form factors f l (q), f m (q) can be parameterized within the Independent Atom Model (IAM) and N l (N m ) the number of atoms of type l (m) in the simulation cell. g 0 w l wm = 0 when w l = u and w m = u, and 1 otherwise . The equation is split up in two terms: the first term is the self-scattering and the second term contains the interatomic structure. The Kronecker delta, δ w l wm , assures there is no double-counting of self-scattering terms.