TY  - JOUR
AU  - Prager, M.
AU  - Press, W.
TI  - Methane clathrate: CH4 quantum rotor state dependent rattling potential
JO  - The journal of chemical physics
VL  - 125
SN  - 0021-9606
CY  - Melville, NY
PB  - American Institute of Physics
M1  - PreJuSER-57070
SP  - 214703
PY  - 2006
N1  - Record converted from VDB: 12.11.2012
AB  - 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.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:17166036
UR  - <Go to ISI:>//WOS:000242646200029
DO  - DOI:10.1063/1.2400031
UR  - https://juser.fz-juelich.de/record/57070
ER  -