where the quantity in the numerator is the mean square displacement (MSD), averaged over the trajectories of individual particles. Diffusion coefficients calculated with MD simulation are often referred to as D P BC , because they contain systematic errors due to the finite box size. Following Ref., it is possible to correct this artifact obtaining the theoretical value of self-diffusion coefficient of water in an infinite box (D 0 ). To this end, we calculated D P BC in cubic simulation cells with N = 512, 1024, 2048, 4096 and 8192 water molecules. The protocol used for these simulations is identical to the one described in section , except for a different production time, i.e., 20 ns (N = 512), 15 ns (N = 1024, 2048), 10 ns (N = 4096, 8192). We calculated the various D P BC values using the gmx msd routine of GROMACS, and D 0 with linear interpolation. Experimental reference data are taken from Ref. Enthalpy of vaporization. The enthalpy of vaporization ∆H vap of one mole of liquid water in the gas phase can be approximated as: 49