Structure Factor¶
The structure factor describes how incident radiation scatters from material.The scattering of X-ray radiation can be described using the partial structure factors \(S_{\alpha \beta}\), which were introduced by Faber and Zimann. Using this formalism the partial structure factor in dependence of the magnitude of the scattering vector \(Q\)
can be calculated requiring only knowledge of the radial distribution function \(g_{\alpha \beta }(r)\) and the particle density \(\rho\). The total structure factor \(S(Q)\) is calculated using a weighted sum of the partial structure factors as described in Tovey et. al. and Keen
The weights are determined using the atomic form factors \(f_i(Q)\) of species i and the molar fraction \(c_i\)
The atomic form factors depend on the type and charge of the element and are approximated by a sum of gaussians, whose coeffients are taken from TU Graz. The atomic form factors are valid for a range of \(0 < Q < 25 \, \text{Å} ^{-1}\). In order for the calculation to work the element names and charges need to be set in the species dictionary as shown in the sample script structure_factor.py .