Clathrate ices -- recent results
Abstract The last five years have seen an increasing interest in clathrate ices as a result of the discovery of extensive deposits of natural gas hydrates in permafrost regions. Twenty-six new clathrate hydrates have been identified, mainly by NMR, including a tetragonal hydrate of dimethyl ether. N...
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ftopenaccessrep:oai:zenodo.org:90635 2023-10-25T01:42:48+02:00 Clathrate ices -- recent results D. W. Davidson J. A. Ripmeester 1978-01-01 https://www.openaccessrepository.it/record/90635 https://doi.org/10.1017/s0022143000033281 eng eng url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/90635 doi:10.1017/s0022143000033281 info:eu-repo/semantics/openAccess NEANIAS Atmospheric Research Community Earth-Surface Processes info:eu-repo/semantics/article publication-article 1978 ftopenaccessrep https://doi.org/10.1017/s0022143000033281 2023-09-26T22:18:15Z Abstract The last five years have seen an increasing interest in clathrate ices as a result of the discovery of extensive deposits of natural gas hydrates in permafrost regions. Twenty-six new clathrate hydrates have been identified, mainly by NMR, including a tetragonal hydrate of dimethyl ether. N-butane and neopentane have been found to be enclathrated in natural gas hydrates, the former as a gauche conformer. As a result of their high symmetries, encaged neopentane, CF4, SF6, and SeF6 exhibit a Resing apparent-phase-change effect in the temperature range of NMR line narrowing. There is increasing evidence that reorientational jumps of water molecules are more frequent than translational jumps in clathrate ices. This is certainly so for ethylene oxide-d4 and tetrahydrofuran-d8 hydrates for which two regions of proton line narrowing and two T 1ρ minima have been observed. The reorientational motions of most guest molecules in structure II hydrates only become isotropic on a time scale long enough to permit the cage configurations to be averaged to 4 3m symmetry by reorientation of the water molecules. The orientations of the water molecules remain disordered to the lowest temperatures. Article in Journal/Newspaper permafrost Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository Gauche ENVELOPE(-62.500,-62.500,-64.233,-64.233) Journal of Glaciology 21 85 33 49 |
institution |
Open Polar |
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Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository |
op_collection_id |
ftopenaccessrep |
language |
English |
topic |
NEANIAS Atmospheric Research Community Earth-Surface Processes |
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NEANIAS Atmospheric Research Community Earth-Surface Processes D. W. Davidson J. A. Ripmeester Clathrate ices -- recent results |
topic_facet |
NEANIAS Atmospheric Research Community Earth-Surface Processes |
description |
Abstract The last five years have seen an increasing interest in clathrate ices as a result of the discovery of extensive deposits of natural gas hydrates in permafrost regions. Twenty-six new clathrate hydrates have been identified, mainly by NMR, including a tetragonal hydrate of dimethyl ether. N-butane and neopentane have been found to be enclathrated in natural gas hydrates, the former as a gauche conformer. As a result of their high symmetries, encaged neopentane, CF4, SF6, and SeF6 exhibit a Resing apparent-phase-change effect in the temperature range of NMR line narrowing. There is increasing evidence that reorientational jumps of water molecules are more frequent than translational jumps in clathrate ices. This is certainly so for ethylene oxide-d4 and tetrahydrofuran-d8 hydrates for which two regions of proton line narrowing and two T 1ρ minima have been observed. The reorientational motions of most guest molecules in structure II hydrates only become isotropic on a time scale long enough to permit the cage configurations to be averaged to 4 3m symmetry by reorientation of the water molecules. The orientations of the water molecules remain disordered to the lowest temperatures. |
format |
Article in Journal/Newspaper |
author |
D. W. Davidson J. A. Ripmeester |
author_facet |
D. W. Davidson J. A. Ripmeester |
author_sort |
D. W. Davidson |
title |
Clathrate ices -- recent results |
title_short |
Clathrate ices -- recent results |
title_full |
Clathrate ices -- recent results |
title_fullStr |
Clathrate ices -- recent results |
title_full_unstemmed |
Clathrate ices -- recent results |
title_sort |
clathrate ices -- recent results |
publishDate |
1978 |
url |
https://www.openaccessrepository.it/record/90635 https://doi.org/10.1017/s0022143000033281 |
long_lat |
ENVELOPE(-62.500,-62.500,-64.233,-64.233) |
geographic |
Gauche |
geographic_facet |
Gauche |
genre |
permafrost |
genre_facet |
permafrost |
op_relation |
url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/90635 doi:10.1017/s0022143000033281 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1017/s0022143000033281 |
container_title |
Journal of Glaciology |
container_volume |
21 |
container_issue |
85 |
container_start_page |
33 |
op_container_end_page |
49 |
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1780739482264272896 |