Abstract
We have carried out Raman spectroscopy and X-ray diffraction to 60 GPa of the 1: 1 H2O: H2 clathrate hydrate, which has water molecules in an arrangement similar to pure ices Ic and VII. The pressure dependence of both the vO-H frequency and the intermolecular distance dO-H...O is significantly larger than in pure ice: unexpectedly, both dependencies can be mapped onto those of pure ice by doubling the pressure. Nevertheless, the correlation between vO-H and dO-H...O is the same as in pure ice, making the clathrate a model system for ice at pressures reduced by a factor 2. Thus, the transition to a phase with symmetric hydrogen bonds probably occurs in the range 30-40 GPa, which is significantly lower than that for H2O.
Original language | English |
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Pages (from-to) | 524-530 |
Number of pages | 7 |
Journal | Chemical physics letters |
Volume | 257 |
Issue number | 5-6 |
DOIs | |
Publication status | Published - 2 Aug 1996 |
Externally published | Yes |