4th QuLiS Symposium

Date and TimeF 13:00`17:20, Thu, March 9, 2007
PlaceFMeeting Room in Faculty of Science, (Higashi-Hiroshima Campus) (Room E002)

Lecture: Sotiris XANTHEAS (Pacific Northwest National Laboratory)

Title: A quantitative account of quantum effects in liquid water
Abstract: We report converged quantum statistical mechanical simulations of liquid water with the TTM2.1-F, Thole-Type Model (version 2.1), Flexible, polarizable interaction potential for water [1]. The interaction potential has been parametrized from the results of high level electronic structure calculations for water clusters and has recently been parallelized to run efficiently on parallel architectures in both classical and quantum macroscopic simulations under periodic boundary conditions [2]. Quantum statistical (centroid molecular dynamics) simulations of total length of 600 ps with a 0.05 fs time step for a periodic unit cell of 256 molecules with up to 32 replicas per atom suggest that the quantum effects contribute 1.01}0.02 kcal/mol to the liquid enthalpy of formation at 298K. They furthermore demonstrate for the first time a quantitative agreement with experiment for the heights and broadening of the intramolecular OH and HH peaks in the radial distribution functions [3].

1. G. S. Fanourgakis and S. S. Xantheas, J. Phys. Chem. A 110, 4100 (2006).
2. G. S. Fanourgakis, V. Tipparaju, J. Nieplocha and S. S. Xantheas, Theor. Chem. Acc. 117, 73 (2007).
3. G. S. Fanourgakis, G. K. Schenter and S. S. Xantheas, J. Chem. Phys. 125, 141102 (2006).

Lecture: OKAZAKI, Susumu (Research Center for Computational Science, Okazaki Research Facilities, National Institutes of Natural Science)

Title: Free energy of micelle formation in water
Abstract: Size distribution of SDS micelle in water and its average aggregation number are discussed based upon the molecular dynamics calculation of free energy of micelle formation. Stability of the micelle in water is also discussed from the view point of its structure at a molecular level.

Lecture: TANAKA, Hideki (Department of Chemistry, Okayama University)

Title: Formation of ice nanotube with hydrophobic guests inside carbon nanotube
Abstract: gA composite ice nanotube inside a carbon nanotube has been explored by molecular dynamics and grandcanonical Monte Carlo simulations. It is made from an octagonal ice nanotube whose hollow space contains hydrophobic guest molecules such as neon, argon, and methane. It is shown that the attractive interaction of the guest molecules stabilizes the ice nanotube and that the occupancy of its hollow space is calculated in the same method as applied to clathrate hydrates.

Lecture: SAITÔ, Hazime (Center for Quantum Life Sciences, Hiroshima University)

Title: Hydration of membrane proteins in relation to their functions
Abstract: Water molecules occupying 70%-90% of cells are not only active as solvents for organic or inorganic molecules and also important for maintaining biological functions of a number of proteins and nucleic acids through specific hydration. Much interest has been focused on behavior of bulk water molecules as viewed from MRI as well as effect of hydrated water to a variety of biological macromolecules. We present here how a typical membrane protein, bacteriorhodopsin, is active, in lipid bilayer, as a proton pump to transport water from inside to outside of cell, by communicating with aqueous phase in the lipid-water interface, as analyzed by high resolution solid state NMR.

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