Raman Study of D2O at High Pressures in a Cubic Zirconia Anvil Cell

Using a cubic zirconia anvil cell, a Raman spectroscopic study was carried out to measure the D–O stretch modes in D2O as a function of varying pressure up to 16.7 GPa. The observed Raman spectra of D2O at room temperature show not only that the liquid is stable at atmospheric pressure, but also that two other phases, deuterated ice VI and deuterated ice VII, sequentially appear above 1.2 and 2.4 GPa, respectively. The D–O stretching wavenumbers in the three phases decrease linearly with increase in pressure. The partial ordering of deuterated ice VII, as indicated by the narrowing of the peak width of theA1gmode can also be determined from the peak intensity ratio between theA1gmode and the other two (Eg+B1g) modes. The maximum ordering of the deuterated ice VII occurs at 11.4 GPa.