This title appears in the Scientific Report :
2006
Please use the identifier:
http://hdl.handle.net/2128/19089 in citations.
Please use the identifier: http://dx.doi.org/10.1063/1.2400031 in citations.
Methane clathrate: CH4 quantum rotor state dependent rattling potential
Methane clathrate: CH4 quantum rotor state dependent rattling potential
In methane hydrate the dominant peak in the density of states above 3 meV represents a rattling mode of the guest molecule CH(4) in the large ice cages. This mode shifts from 6.7 meV at T=4.5 K to T=30 K to 7.14 meV with conversion of CH(4) guest molecules into the tunneling ground state. The less s...
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Personal Name(s): | Prager, M. |
---|---|
Press, W. | |
Contributing Institute: |
Neutronenstreuung; IFF-INS |
Published in: | The @journal of chemical physics, 125 (2006) S. 214703 |
Imprint: |
Melville, NY
American Institute of Physics
2006
|
Physical Description: |
214703 |
DOI: |
10.1063/1.2400031 |
PubMed ID: |
17166036 |
Document Type: |
Journal Article |
Research Program: |
Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) Kondensierte Materie |
Series Title: |
Journal of Chemical Physics
125 |
Subject (ZB): | |
Link: |
Get full text OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1063/1.2400031 in citations.
In methane hydrate the dominant peak in the density of states above 3 meV represents a rattling mode of the guest molecule CH(4) in the large ice cages. This mode shifts from 6.7 meV at T=4.5 K to T=30 K to 7.14 meV with conversion of CH(4) guest molecules into the tunneling ground state. The less symmetric angular density distribution PsiPsi(*) in the excited rotational state compared to the ground state allows the methane to fit better in the orientation dependent cage potential surface. This leads to a larger average distance to the cage-forming molecules with a weaker potential and a reduced rattling energy. A two state single particle model with characteristic rattling energies of 5.20 meV for pure T-methane and 7.3 meV for pure A-methane weighted by the population factors can fit the data. |