High-Pressure X-ray Diffraction and Raman Spectroscopy of Ice VIII
Hemley, Russell J.
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CitationYoshimura, Yukihiro, Sarah T. Stewart, Maddury Somayazulu, Ho-kwang Mao, and Russell J. Hemley. 2006. High-pressure x-ray diffraction and Raman spectroscopy of ice VIII. Journal of Chemical Physics 124(2): 024502.
AbstractIn situ high-pressure/low-temperature synchrotron x-ray diffraction and optical Raman spectroscopy were used to examine the structural properties, equation of state, and vibrational dynamics of ice VIII. The x-ray measurements show that the pressure-volume relations remain smooth up to 23 GPa at 80 K. Although there is no evidence for structural changes to at least 14 GPa, the unit-cell axial ratio c/a undergoes changes at 10-14 GPa. Raman measurements carried out at 80 K show that the nu(Tz)A(1g)+nu Tx,yEg lattice modes for the Raman spectra of ice VIII in the lower-frequency regions (50-800 cm(-1)) disappear at around 10 GPa, and then a new peak of similar to 150 cm(-1) appears at 14 GPa. The combined data provide evidence for a transition beginning near 10 GPa. The results are consistent with recent synchrotron far-IR measurements and theoretical calculations. The decompressed phase recovered at ambient pressure transforms to low-density amorphous ice when heated to similar to 125 K.
Citable link to this pagehttp://nrs.harvard.edu/urn-3:HUL.InstRepos:4727478
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