Washington, DC, 21 February 2012- In a combined experimental effort researchers from the Geophysical Laboratory, Oak Ridge National Laboratory and Steacie Institute for Molecular Sciences now have a better understanding of a form of high pressure methane clathrate hydrate.

A recent experiment with the new Spallation Neutrons and Pressure Diffractometer (SNAP) instrument dedicated to high pressure neutron scattering studies has provided definitive experimental results for testing and refining intermolecular potentials used to describe the important hydrophobic interaction which plays a critical role in fields ranging from biology to planetary science.

A combination of a state-of-the-are instrument, clever experimental technique, and excellent samples yielded detailed data on a structure of a high pressure form of a methane clathrate hydrate. The results gave precise information on the number of methane molecules that could fit into the cages of this inclusion compound consisting of only water and methane. This study shows that the correct occupancy for the largest cages in the structure are three methane molecules. This can now be used to benchmark intermolecular potentials for methane and water interactions and should lead to an improved characterization of the hydrophobic interaction.

This study can be found at: C.A.Tulk, et al., Journal of Chemical Physics 136, 054502 (2012).

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