Abstract
Inelastic incoherent neutron scattering spectra of recovered high pressure H2O and D2O ice VIII were measured in the range 2-140 meV at 25 K using the TFXA spectrometer at ISIS. The excellent resoltion of this instrumentyields detailed information on the dynamics of ice VIII, in particular about the translational modes below 35 meV and about the librational modes from 54 to 115 meV for H2O and from 40 to 90 meV for D2O. In the translational region, the first peak in the acoustic mode region is shifted by 7.6 meV towards higher energies as compared to ice Ih. It is also important to note that the strong feature that appears in the inelastic spectra of all other measured ice structures is completely missing from the present spectra for both isotopes. In the librational mode region, the spectrum shows that the low energy cut-off of the librational band shifts 12 meV towards low energy transfers as compared with ice Ih for both isotopes. In addition, two sharp peaks are seen at energy transfers of 55 and 68 meV for H2O (41.5 and 49.9 meV for D2O) which are not seen in other forms of ice.
| Original language | English |
|---|---|
| Pages (from-to) | 308-312 |
| Number of pages | 5 |
| Journal | Physics Letters, Section A: General, Atomic and Solid State Physics |
| Volume | 168 |
| Issue number | 4 |
| DOIs | |
| State | Published - Aug 31 1992 |
| Externally published | Yes |
Funding
We would like to thank the Science and Engineering Research Council (UK) for financial support and the Rutherford Appleton Laboratory for the use of neutron facilities. EHB would also like to acknowledge financial support from the School of Physics and Space Research, University of Birmingham, UK and from the Science and Engineering Research Council.