We perform lengthy molecular dynamics simulations to investigate the dynamics of water under pressure at many temperatures and compare with experimental measurements. We calculate the isochrones of the diffusion constant $D$ and find, as observed experimentally, power-law behavior of $D$ as temperature approaches $T_c\left(P\right)$. We find that the dynamics are consistent with slowing down due to the transient caging of molecules, as described by the mode-coupling theory (MCT). This supports the hypothesis that the apparent divergences of dynamic quantities along the line $T_c\left(P\right)$ in water may be associated with “slowing down” as predicted by MCT.

• Received 31 December 1998

DOI:https://doi.org/10.1103/PhysRevLett.82.3629