Inelastic incoherent neutron scattering study of D2O and H2O ice VIII in the range 2–140 meV
1992; Elsevier BV; Volume: 168; Issue: 4 Linguagem: Inglês
10.1016/0375-9601(92)91138-h
ISSN1873-2429
AutoresА. И. Колесников, J.-C. Li, D.K. Ross, V.V. Sinitzin, O.I. Barkalov, É. L. Bokhenkov, E. G. Ponyatovskiǐ,
Tópico(s)Methane Hydrates and Related Phenomena
ResumoInelastic 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.
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