Electric-Field Control of Neon Uptake and Release to and from Clathrate Hydrates

The thermodynamic and kinetic properties of neon uptake and release to and from a sII clathrate hydrate were evaluated using molecular dynamics simulation in the absence and presence of an applied static electric field. In the case of neon “leakage”, neon clathrate in contact with a vacuum was simulated at temperatures ranging from 200 to 225 K for 0.5 μs, with progressive neon-emptying of cages monitored. Activation energies for release and uptake were 16.4 and 14.9 kJ/mol, respectively—consistent with experimentally determined values; for neon release in a 0.7 V/nm electric field, the value declines to 6.5 kJ/mol, suggesting its use as a control agent in facilitating gas release from already-loaded clathrates. For neon uptake into an initially empty hydrate, loading free energies for 512 and 51264 cages, computed via thermodynamic integration, was lower than that previously reported for methane uptake into sI hydrates.