Quantum rotations in natural methane-clathrates from the Pacific sea-floor
We report inelastic neutron scattering experiments from natural methane hydrates sampled from the Pacific sea-floor during an expedition of the research ship SONNE. The experiments verify directly the content of methane by measuring the rotational spectrum of the $\rm CH_4$ molecules. The existence...
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Veröffentlicht in: | Europhysics letters 1999-11, Vol.48 (3), p.269-275 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | We report inelastic neutron scattering experiments from natural methane hydrates sampled from the Pacific sea-floor during an expedition of the research ship SONNE. The experiments verify directly the content of methane by measuring the rotational spectrum of the $\rm CH_4$ molecules. The existence of almost free rotational levels excludes off-center positions of the molecules in the cages. In addition we could assign the observed peaks in the energy regime up to 5 meV to rotational excitations only. The observed relative sharp excitations prove a surprisingly good crystallinity of the geological sample. The finite width is attributed to frozen-in hydrogen disorder of the ice cages. |
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ISSN: | 0295-5075 1286-4854 |
DOI: | 10.1209/epl/i1999-00476-x |