PHYS 535 |
| The dynamics of water in aqueous solutions plays an important role in many important applications including the crystallization of proteins and the conformational behavior of peptides and nucleic acids. The behavior of supercooled water is interesting in the context of crystallization and the effect of anti-freeze proteins on nucleation and growth. In this work we present molecular dynamics simulations for the structure and dynamics of water in aqueous sodium chloride solutions. At temperatures above the freezing point of pure water, the self-diffusion coefficient is a monotonically decreasing function of salt concentration. Below the freezing point of pure water, however, the self-diffusion coefficient is a non-monotonic function of salt concentration, showing a maximum at approximately one molal salt. This suggests that sodium chloride, which is considered a structure-making salt at room temperature, becomes a structure-breaking salt at low temperatures. A qualitative understanding of this effect is obtained by considering the effect of ions on the residence time of water molecules near other water molecules.
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PHYS Poster Session - General Theory
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster
Division of Physical Chemistry |
