Characterization of a cage form of the water hexamer
Water has been studied more extensively than any other liquid, yet its microscopic properties remain poorly understood. The difficulty in obtaining a rigorous molecular-scale description of water structure is largely a consequence of the extended, dynamic hydrogen-bonded network that exists througho...
| Main Authors: | , , , , , |
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| Format: | Journal article |
| Published: |
1996
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| Summary: | Water has been studied more extensively than any other liquid, yet its microscopic properties remain poorly understood. The difficulty in obtaining a rigorous molecular-scale description of water structure is largely a consequence of the extended, dynamic hydrogen-bonded network that exists throughout the liquid1. Studies of the structure and dynamics of isolated small clusters of water molecules2-6 provide a means of quantifying the intermolecular forces and hydrogen-bond rearrangements that occur in condensed phases. Experiments2-7 and theory8 strongly suggest that the water trimer, tetramer and pentamer have cyclic minimum energy structures. Larger water clusters are expected8 to have three-dimensional geometries, with the hexamer representing the transition from cyclic to such three-dimensional structures. Here we report investigations by terahertz laser vibration-rotation tunnelling spectroscopy3 of the structure of the water hexamer. A comparison of our results with quantum Monte Carlo simulations of this species suggests that the most stable form of (H2O)6 is indeed a cage-like structure, held together by eight hydrogen bonds (Fig. 1). |
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