Fig. 3.
Molecular dipole moments and the finite-system Kirkwood factor (Gk) of water under pressure. Shown are the distribution of the molecular dipole moment of water obtained in ab initio MD simulations (Left) and the variation of Gk with pressure (Right). (Left) Vertical lines indicate the fixed value of the dipole moment of water in the SPC/E model. Temperatures are 1,000 K (Upper) and 2,000 K (Lower), respectively. (Right) Results obtained with both ab initio simulations (DFT-PBE) and the empirical potential SPC/E are shown.