Dresden 2009 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 7: Liquids
CPP 7.4: Talk
Monday, March 23, 2009, 18:45–19:00, ZEU 160
Tetrahydrofuran clathrate hydrate formation studied by non-resonant inelastic x-ray scattering — •Felix Lehmkühler1, Christian Sternemann1, Heiko Conrad1, Arto Sakko2, Mikko Hakala2, Kim Nygård3, Dietmar Paschek4, Omid Feroughi1, Thomas Buslaps5, Laura Simonelli5, Metin Tolan1, and Keijo Hämäläinen2 — 1TU Dortmund, Fakultät Physik/DELTA, Dortmund, Germany — 2Division of Materials Physics, Department of Physics, FIN-00014 University of Helsinki, Finland — 3Paul Scherrer Institut, Villigen PSI, Switzerland — 4Rensselaer Polytechnic Institute, Troy, 12180 NY, USA — 5ESRF, 38043 Grenoble, France
Clathrate hydrates are ice-like inclusion compounds where guest molecules are embedded in water nano-cages. A possible future application of hydrates is the storage of gases, especially H2 in THF hydrate for fuel cells. In general, the hydrate formation on a microscopic level is still not understood. Competing formation models are reported in literature, which predict hydrate precursors in a supercooled state before the hydrate nucleation starts or a stochastic formation without any hydrate pre-structures.
The bulk formation in the system water-THF was investigated by measuring x-ray Compton profiles and non-resonant x-ray Raman spectra of the hydrate, a mixture at temperatures above the region of hydrate stability, and the supercooled liquid mixture in order to detect hydrate precursors. The measurements were compared with DFT calculations employing local structures obtained from molecular dynamics simulation snapshots.