Figure 1. X-ray and neutron diffraction total structure factors S(q) for liquid Ge₂Sb₂Te₅ measured at 923 K (blue curves) compared to the structure factors obtained from vdW-DF2 and GGA AIMD simulations at 925–926 K (black and green curves respectively) and RMC simulations (red curves).

The AIMD S(q) are computed from the partial structure factors S_ij(q) weighted by the X-ray or neutron atomic form factors. The partial factors S_ij(q) are calculated by Fourier transforming the partial pair correlation functions (shown in Fig. 2).