| Download | - View accepted manuscript: Water molecular reorientation in ice and tetrahydrofuran clathrate hydrate from lineshape analysis of 17O spin-echo NMR spectra (PDF, 943 KiB)
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| DOI | Resolve DOI: https://doi.org/10.1139/v11-040 |
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| Author | Search for: Ba, Yong1; Search for: Ripmeester, John A.1; Search for: Ratcliffe, Christopher I.1 |
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| Affiliation | - National Research Council of Canada. NRC Steacie Institute for Molecular Sciences
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| Format | Text, Article |
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| Subject | ice-Ih, THF clathrate hydrate, 17O NMR, molecular reorientations of solid water, Kinetics, residual second order quadrupolar shift, dynamics of non-integer quadrupolar nuclei |
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| Abstract | Lineshape analysis of 17O spin-echo NMR spectra has been used to study water molecular reorientations in ice-Ih and THF Structure II clathrate hydrate. The kinetics was determined by the changes of the lineshapes of the 17O central transitions at different temperatures. A model involving 12 orientations and 4-step jumps of water molecular orientations was proposed. Semi-classical exchange formalism was employed to simulate the lineshape of the central transitions of the 17O nuclei. Lineshape analysis gave the quadrupolar coupling constant CQ = 6.43 MHz and the asymmetry parameter η = 0.935, for both ice-Ih and THF gas hydrate. The theoretical lineshape simulations resulted in activation energies of water molecular reorientations Ea = 55.2 ± 2.1 kJ mol–1 and Ea = 30.5 ± 0.8 kJ mol–1 for ice-Ih and THF hydrate, respectively. The range of dynamic rates in THF clathrate hydrate is such that before melting, a pseudo-isotropic lineshape is observed that retains a second-order quadrupolar shift. The water reorientation process is discussed in light of recent results on Bjerrum defect injection obtained from molecular dynamics simulation and structural studies. |
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| Publication date | 2011-08-19 |
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| In | |
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| Language | English |
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| Peer reviewed | Yes |
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| NPARC number | 19727323 |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | 07809cc3-4a2b-406a-b0c3-4588165f0ded |
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| Record created | 2012-03-29 |
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| Record modified | 2020-04-21 |
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