Figure 7: Dynamic viscosity η of liquid Ge2Sb2Te5 measured experimentally (blue circles) and calculated from the diffusivity derived from the vdW-DF2 AIMD trajectories by applying Stokes-Einstein relation (black diamonds).

The lines are the fits with the Arrhenius equation . For the theoretical viscosity, one obtains η0 = 0.140 mPa s, Ea = 0.256 eV; fitting of the experimental data instead yields η0 = 0.063 mPa s and Ea = 0.266 eV.