Anomalous Water

We will investigate liquid water structure by focusing on the dissolution of simple gases (O2 and Argon) using theoretical simulations in conjunction with X-ray experiments.

These gases interact weakly with water and we propose to use them as probes of regions of lower density in the liquid where they can fit in.

Experimentally we plan to measure EXAFS of Argon in water combined with theoretical simulations of the EXAFS signal based on a multiple-scattering approach.

Water in polyelectrolyte brushes on a substrate has been shown to be highly tetrahedral but with more disorder than in ice, thus possibly facilitating gas transport from the liquid into the polyelectrolyte structure.

A similar structure with entangled proteins and saccharides is also observed at the interface between gills of fish and bulk water.

In a two-state picture of water, with fluctuating low- and high-density regions where O2 prefers low-density cavities, such an arrangement can assist in extracting the gas from water.

We will simulate and experimentally study gas transfer from the liquid to model membranes which may shed light on how fish extract oxygen from water.

We will develop and apply an improved force-field description of water and its interaction with gases with particular emphasis on the description of the isothermal compressibility which depends on structural fluctuations that are strongly underestimated in present force-fields for water and could be of relevance for the dissolution of gases.