6533b827fe1ef96bd12871fe
RESEARCH PRODUCT
Amorphous polymorphis in ice investigated by inelastic neutron scattering
A. TölleHelmut SchoberMichael Marek KozaFranz FujaraRoland BöhmerCharles Angellsubject
Materials scienceEnergy windowCondensed matter physicsbusiness.industryPhononTime evolutionCondensed Matter Physics530Ice IcInelastic neutron scatteringSpectral lineElectronic Optical and Magnetic MaterialsAmorphous solidOpticsAmorphous iceElectrical and Electronic Engineeringbusinessdescription
Abstract High-density Ilda and low-density Ilda amorphous have been investigated by inelastic neutron scattering (INS) with emphasis on the energy window from 0.5 to 20 meV. At variance with earlier measurements the spectra in the Ilda phase show a simple ω2 behaviour in the acoustic region and the temperature dependence is found to be harmonic. Ilda converts with a strongly temperature-dependent rate towards Ilda ice. We have investigated in detail the time evolution of both the static and dynamic response functions at several temperatures. Elastic small-angle signals indicate the presence of strong heterogeneties at the early stages of the conversion process. At least two different time scales are present in the transition. The structural changes are reflected in the frequency distribution. The first peak in the phonon density-of-states softens appreciably when going from Ilda to Ilda. In the acoustic region there is evidence that Ilda is softer than both Ilda and crystalline cubic ice Ic. No signs of a fast ps process related to melting can be detected in the dynamics.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1997-12-01 | Physica B: Condensed Matter |