Water Structure and Dynamics
1. Field Theory of Liquid Water (Hidden structures with long lifetime)
In liquid phase water molecules are mutually connected by hydrogen bond network.
Water molecules move in a cooperative way associating with the network rearrangement.
Using molecular dynamics simulation, mesoscopic long lifetime structure in the network is analyzed.
Patterns in the figure is distribution of dipoles defined at each spatial position as a field quantity.
J. Higo, M. Sasai, H. Shirai, H. Nakamura & T. Kugimiya, "Large vortex-like structure of dipole field in computer models of liquid water and dipole-bridge between biomolecules", Proc. Natl. Acad. Sci. USA 98(11) 5961-5964 (2001).
T. Hotta, A. Kimura & M. Sasai, "Fluctuating Hydration Structure around Nanometer-Size Hydrophobic Soutes I - Caging and Drying around C60 and C60H60 Spheres -", J. Phys. Chem. B109(39) 18600-18608 (2005).
T. Hotta & M. Sasai, "Fluctuating Hydration Structure around Nanometer-Size Hydrophobic Soutes II - Caging and Drying around Single Wall Carbon Nanotubes -", J. Phys. Chem. C111(7) 2861-2871 (2007).
T. Hotta, A. Kimura & M. Sasai, "Fluctuating Hydration Structure around Nanometer-Size Hydrophobic Soutes I - Caging and Drying around C60 and C60H60 Spheres -", J. Phys. Chem. B109(39) 18600-18608 (2005).
T. Hotta & M. Sasai, "Fluctuating Hydration Structure around Nanometer-Size Hydrophobic Soutes II - Caging and Drying around Single Wall Carbon Nanotubes -", J. Phys. Chem. C111(7) 2861-2871 (2007).
2. Slow Dynamics and Glass Transition in Liquid Water (Energy landscape picture)
Structure and dynamics of hydrogen bonds among water molecules are studied by using mean-field theories and molecular dynamic simulations.
Local structural order parameter of hydrogen bond network are found in simulation.
The large intermittent fluctuation of the local structure of the network in room temperature is a precursor of the liquid-liquid transition of water in low temperature.
The slow relaxation of the low temperature water was studied from the energy landscape point of view and was compared with glass transitions in other liquids.
E. Shiratani & M. Sasai, "Molecular scale precursor of the liquid-liquid phase transition of water", J. Chem. Phys. 108(8) 3264-3276 (1998).
M. Sasai, "Spatiotemporal heterogeneity and energy landscape in liquid water", Physica A 285(3-4) 315-324 (2000).
M. Sasai, "Energy landscape picture of supercooled liquids: Application of a generalized random energy model", J. Chem. Phys. 118(23) 10651-10662 (2003).
M. Sasai, "Spatiotemporal heterogeneity and energy landscape in liquid water", Physica A 285(3-4) 315-324 (2000).
M. Sasai, "Energy landscape picture of supercooled liquids: Application of a generalized random energy model", J. Chem. Phys. 118(23) 10651-10662 (2003).