The dynamics predicted by DFT functionals depends on their ability to account for hydrogen bond strength as well as directionality. Diffusion and rotational movements are determined by the dynamic breaking and formation of H-bonds under thermal fluctuations. Therefore, if the description of H-bonds is too strong, it significantly slows down the dynamical properties. Local and semilocal functionals suffer from the self-interaction error that promotes a delocalization of the protons 140,161 . This declocalization facilitates the formation of H-bonds when the proton moves toward the acceptor and thus contributes to the H-bond strengthening, in an analogous manner to the NQEs (Section 3.1.2). As an illustration, the diffusion coefficient is too low for most GGA and meta-GGA functionals, in agreement with their tendency to with experimental results overstructure. For example, optB88-vdW yields slightly overstructured water (Fig. ), and diffuses too slowly (Fig. ). BLYP-DCACP and revPBE have higher diffusion coefficients, more in line with experiment, but this originates from their underestimation of the number of hydrogen bonds (Fig. ).