High temperatures and high pressures Brillouin scattering studies of liquid H2O+CO2 mixtures

The Brillouin scattering spectroscopy studies have been conducted in a diamond anvil cell for a liquid mixtures composed of 95 mol % H2O and 5 mol % CO2 under high temperatures and pressures. The sound velocity, refractive index, density, and adiabatic bulk modulus of the H2O+CO2 mixtures were determined under pressures up to the freezing point at 293, 453, and 575 K. It is found from the experiment that sound velocities of the liquid mixture are substantially lower than those of pure water at 575 K, but not at lower temperatures. We presented an empirical relation of the density in terms of pressure and temperature. Our results show that liquid H2O+CO2 mixtures are more compressible than water obtained from an existing equation of state of at 453 and 575 K. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3495972]