Figure shows a log-log representation of the size of the relative uncertainty σD0 /D 0 , vs. the total number of molecules N in the simulation. The data shown represent averages over data from all four pure liquid simulations (water, dimethyl ether, methanol, triglyme), (2) averages over data from the individual components of the two molecular mixtures (methanol/water, triglyme/water), and (3) the average over the two components of the ionic liquid [BMim][PF 6 ]. For the pure liquids and liquid mixtures the average relative uncertainty for D 0 consistently varies between 0.38% and 0.76%. Although the data obtained for the individual components and mixtures shown in Tables II, III, and IV show a little bit of variation, we can state, that the approach outlined in section III leads to a rather consistent size of the computed relative error for D 0 , and therefore also for the viscosity η. Moreover, the plot of the data for pure liquids and mixtures in Figure is leading to a scaling of σD0 /D 0 ∝ N -β/2 with β ≈ 0.65. We would like to point out that this scaling behavior is markedly deviating from the ideal value of β = 1, but it is in line with the observation of Jamali et al. , who reported a scaling of the error of the computed self-diffusion coefficients with the system size of σDPBC ∝ N -1/3 for various liquids obtained from MD simulations based on cubic systems. However, the data for the ionic liquid [BMim][PF 6 ] strongly deviates from this common scaling behavior, exhibiting a significantly smaller exponent of β ≈ 0.37. If the trajectories of all the particles in a simulation were statistically independent from one another, the scaling would correspond to an exponent of β = 1. The scaling behavior observed here is due to a correlation effect based on the mutual interaction of the diffusing particles. It is therefore perhaps not too surprising that the particularly strong mutual interaction between ions is leading to an even more enhanced correlation of the diffusion data in the studied ionic liquid system.