Morphological change of ice Ih under pressure.

Phase transition mechanism of sH to filled-ice Ih of methane hydrate under fixed pressure condition

Melting of ice under pressure.

The melting of ice under pressure is investigated with a series of first-principles molecular dynamics simulations. In particular, a two-phase approach is used to determine the melting temperature of the ice-VII phase in the range of 10-50 GPa. Our computed melting temperatures are consistent with existing diamond anvil cell experiments. We find that for pressures between 10 and 40 GPa, ice mel...

Diffuse scattering in Ih ice.

Single crystals of ice Ih, extracted from the subglacial Lake Vostok accretion ice layer (3621 m depth) were investigated by means of diffuse x-ray scattering and inelastic x-ray scattering. The diffuse scattering was identified as mainly inelastic and rationalized in the frame of ab initio calculations for the ordered ice XI approximant. Together with Monte-Carlo modelling, our data allowed re...

Two-dimensional infrared spectroscopy of isotope-diluted ice Ih.

We present experimental 2D IR spectra of isotope diluted ice Ih (i.e., the OH stretch mode of HOD in D(2)O and the OD stretch mode of HOD in H(2)O) at T = 80 K. The main spectral features are the extremely broad 1-2 excited state transition, much broader than the corresponding 0-1 groundstate transition, as well as the presence of quantum beats. We do not observe any inhomogeneous broadening th...

Convergent Raman features in high density amorphous ice, ice VII, and ice VIII under pressure.

The high-pressure behavior of H(2)O ice at temperatures below 100 K has been investigated to 20 GPa by Raman spectroscopy. Between 10 and 80 K, high density amorphous (hda) ice formed from ice I(h) undergoes a phase transition near 5 GPa to ice VII' and a transition at 14 GPa to a different phase. At 14 GPa, a new low-frequency band appears at ~150 cm(-1) that steeply increases in frequency wit...