How the liquid-liquid transition affects hydrophobic hydration in deeply supercooled water.

We determine the phase diagram of liquid supercooled water by extensive computer simulations using the TIP5P-E model. We find that the transformation of water into a low density liquid in the supercooled range strongly enhances the solubility of hydrophobic particles. The transformation of water into a tetrahedrally structured liquid is accompanied by a minimum in the hydration entropy and enthalpy. The corresponding change in sign of the solvation heat capacity indicates a loss of one characteristic signature of hydrophobic hydration. The observed behavior is found to be qualitatively in accordance with the predictions of the information theory model of Garde et al.