The lateral (two-dimensional, 2D) diffusion coefficient, D W , of the confined water has been calculated from the mean square displacement for all the six water models (for details, see the Supplementary Information, Figure ). For comparison D W of bulk water has also been that in order to obtain agreement, DFT simulations have to be performed at much higher temperature (to reproduce the room temperature experiment one has to use a temperature of about 400 K). Given this state of affairs we refrain from a quantitative comparison with experiment, but focus on the relative changes in situations of confined water within the present computational setup. Here we find that the 2D diffusion for the confined water slows down to the range from 0.63 × 10 -5 to 0.87 × 10 -5 cm 2 /s for the present models (cf.