Slow Dynamics of Water under Pressure

Abstract

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 ${T}_{c}(P)$. 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 ${T}_{c}(P)$ in water may be associated with ``slowing down'' as predicted by MCT.