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We examine the role of electronic polarizability in water on short (tens of femtoseconds), intermediate (hundreds of femtoseconds), and long ([approximately equal to]1 ps) time scales by comparing molecular dynamics results to experimental data for vibrational spectroscopy of HOD in liquid [D.sub.2]O. Because the OH absorption frequency is sensitive to the details of the atomic forces experienced in the liquid, our results provide important quantitative comparisons for several popular empirical water potentials. When compared with their fixed-charge counterparts, the polarizable models give similar slower long time constants for the decay of vibrational correlations and reorientational motion that is in better agreement with experiments. Polarizable potentials yield qualitatively dissimilar predictions for frequency fluctuations and transition dipole moment fluctuations at equilibrium. Models that confine the polarizability to the plane of the molecule (i.e., TIP4P-FQ) overestimate the width of the distribution describing frequency fluctuations by more than a factor of two. These models also underestimate the amplitude of the hydrogen-bond stretch at 170 [cm.sup.-1]. A potential that has both an out-of-plane polarization and fluctuating charges, POL5-TZ, compares best with experiments. We interpret our findings in terms of microscopic dynamics and make suggestions that may improve the quality of emerging polarizable force fields for water. hydrogen-bond dynamics | molecular dynamics | polarizable force fields

Molecular dynamics simulations are used to examine the solvent mediated attraction and drying between two nanoscale hydrophobic surfaces in aqueous salt solutions. The results have shown the unique effects of electrolytes on the hydrophobic properties of solutes of various sizes, ranging from small nanoscale particles to large nanoscale surfaces.

An investigation on the effect of salts on the solvent-induced interactions between hydrophobic particles dispersed in explicit aqueous solution is conducted as a function of the salt's ionic charge density by molecular dynamics simulations. The aggregate is found to form a 'micelle-like' structure, in which the ions are preferentially adsorbed at the surface of the aggregate, at low concentrations of low charge density ions.

Molecular dynamics simulations are performed to study the dynamics of interfacial water confined in the interdomain region of a two-domain protein, BphC enzyme. The results show that near the protein surface the water diffusion constant is much smaller and the water-water hydrogen bond lifetime is much longer than that in bulk.

A modified Delphi model combined with a molecular dynamics method is devised to calculate the free energy landscape of a small protein. Based on the replica exchange method (REM), the molecular dynamics method is used to sample the conformational space of the beta-hairpin, the C-terminus beta-hairpin of protein G, as before.

A general method to calculate the self-diffusion coefficient tensor from molecular dynamics (MD) in a finite region is proposed. The results revealed that far from the interface the diffusion tensor is found of distance as expected, and the diffusion coefficient has the value D approximately is 0.22 A degree 2/ps, in agreement with what is found in the bulk liquid.