Water clusters in nonpolar cavities
- *Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Building 5, Bethesda, MD 20892-0520; and Departments of †Physics and Astronomy and §Chemistry, University of Maine, Orono, ME 04469
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Communicated by Johanna M. H. Levelt Sengers, National Institute of Standards and Technology, Gaithersburg, MD, October 26, 2004 (received for review August 20, 2004)
Abstract
We explore the structure and thermodynamics of water clusters confined in nonpolar cavities. By calculating the grand-canonical partition function term by term, we show that small nonpolar cavities can be filled at equilibrium with highly structured water clusters. The structural and thermodynamic properties of these encapsulated water clusters are similar to those observed experimentally in the gas phase. Water filling is highly sensitive to the size of the cavity and the strength of the interactions with the cavity wall. Water penetration into pores can thus be modulated by small changes in the polarity and structure of the cavity. Implications on water penetration into proteins are discussed.
