Diffusive hydrogen inter-cage migration in hydrogen and hydrogen-tetrahydrofuran clathrate hydrates
|Title:||Diffusive hydrogen inter-cage migration in hydrogen and hydrogen-tetrahydrofuran clathrate hydrates||Authors:||Cao, Huayu; English, Niall J.; MacElroy, J. M. Don||Permanent link:||http://hdl.handle.net/10197/5234||Date:||7-Mar-2013||Online since:||2014-01-14T09:32:58Z||Abstract:||Classical equilibrium molecular dynamics (MD) simulations have been performed to investigate the diffusive properties of inter-cage hydrogen migration in both pure hydrogen and mixed hydrogen-tetrahydrofuran sII hydrates at 0.05 kbar from 200 K and up to 250-260 K. For mixed H2- THF systems in which there is single H2 occupation of the small cage (labelled ‘1SC 1LC’), we found that no H2 migration occurs. However, for more densely-filled H2-THF and pure- H2 systems, in which there is more than single H2 occupation in the small cage, there is an onset of inter-cage H2 migration events from the small cages to neighbouring cavities at around 200 K. The mean square displacements of the hydrogen molecules were fitted to a mathematical model consisting of an anomalous term and a Fickian component, and non-linear regression fitting was conducted to estimate long-time (inter-cage) diffusivities. An approximate Arrhenius temperature relationship for the diffusion coefficient was examined and a rough estimation of the hydrogen hopping energy barrier was calculated for each system.||Funding Details:||Science Foundation Ireland||Type of material:||Journal Article||Publisher:||American Institute of Physics||Journal:||The Journal of Chemical Physics||Volume:||138||Issue:||9||Start page:||094507||Copyright (published version):||2013 American Institute of Physics||Keywords:||Molecular dynamics; Hydrogen hydrate; THF hydrate; Diffusion; Migration; Fickian||DOI:||10.1063/1.4793468||Language:||en||Status of Item:||Peer reviewed||This item is made available under a Creative Commons License:||https://creativecommons.org/licenses/by-nc-nd/3.0/ie/|
|Appears in Collections:||Chemical and Bioprocess Engineering Research Collection|
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