The effect of the water/methane interface on methane hydrate cages: The potential of mean force and cage lifetimes

Molecular dynamics simulations were used to determine the influence of a methane-water interface on the position and stability of methane hydrate cages. A potential of mean force was calculated as a function of the separation of a methane hydrate cage and a methane-water interface. The hydrate cages...

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Bibliographic Details
Published in:The Journal of Chemical Physics
Main Authors: Mastny, Ethan A., Miller, Clark A., de Pablo, Juan J.
Format: Article in Journal/Newspaper
Language:English
Published: AIP Publishing 2008
Subjects:
Online Access:http://dx.doi.org/10.1063/1.2925680
https://pubs.aip.org/aip/jcp/article-pdf/doi/10.1063/1.2925680/15417350/034701_1_online.pdf
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Summary:Molecular dynamics simulations were used to determine the influence of a methane-water interface on the position and stability of methane hydrate cages. A potential of mean force was calculated as a function of the separation of a methane hydrate cage and a methane-water interface. The hydrate cages are found to be strongly repelled from the methane gas into the water phase. At low enough temperatures, however, the most favorable location for the hydrate cage is at the interface on the water side. Cage lifetime simulations were performed in bulk water and near a methane-water interface. The methane-water interface increases the cage lifetime by almost a factor of 2 compared to cage lifetimes of cages in bulk water. The potential of mean force and the cage lifetime results give additional explanations for the proposed nucleation of gas hydrates at gas-water interfaces.