Supercooled confined water and the Mode Coupling Crossover Temperature.

We present a molecular dynamics study of the single-particle dynamics of supercooled water confined in a silica pore. Two dynamical regimes are found. Close to the hydrophilic substrate molecules are below the mode coupling crossover temperature, T-C, already at ambient temperature. The water closer to the center of the pore (free water) approaches upon supercooling T-C as predicted by mode coupling theories. For free water the crossover temperature and crossover exponent gamma are extracted from power-law fits to both the diffusion coefficient and the relaxation time of the late alpha region.