Kumar, PradeepFranzese, GiancarloStanley, H. Eugene (Harry Eugene), 1941-2010-07-052010-07-0520080031-9007https://hdl.handle.net/2445/13290Using Monte Carlo simulations and mean field calculations for a cell model of water we find a dynamic crossover in the orientational correlation time $\tau$ from non-Arrhenius behavior at high temperatures to Arrhenius behavior at low temperatures. This dynamic crossover is independent of whether water at very low temperature is charaterized by a ``liquid-liquid critical point'' or by the ``singularity free'' scenario. We relate $\tau$ to fluctuations of hydrogen bond network and show that the crossover found for $\tau$ for both scenarios is a consequence of the sharp change in the average number of hydrogen bonds at the temperature of the specific heat maximum. We find that the effect of pressure on the dynamics is strikingly different in the two scenarios, offering a means to distinguish between them.4 p.application/pdfeng(c) American Physical Society, 2008Transformacions de fase (Física estadística)Física estadísticaPhase transformations (Statistical physics)Statistical physicsinfo:eu-repo/semantics/article558138info:eu-repo/semantics/openAccess