High-temperature Raman spectroscopic study of H (sub 2) O-CO (sub 2) -CH (sub 4) mixtures in synthetic fluid inclusions; first insights on molecular interactions and analytical implications

Raman spectra of fluids of the CO (sub 2) -CH (sub 4) -H (sub 2) O and CO (sub 2) -H (sub 2) O systems contained in synthetic fluid inclusions have been obtained above the homogenization T to 500 degrees C. Spectra of CO (sub 2) and CH (sub 4) do not vary along the portion of the isochore studied, but they do for the symmetric stretching band of water. The spectra clearly show that molecular interactions are stronger between CO (sub 2) and H (sub 2) O than between CH (sub 4) and H (sub 2) O molecules. Gas molecules decrease the signature of hydrogen bonding in the Raman spectrum of water. For water-rich fluids, the ratio of Raman scattering cross-secion of CH (sub 4) and H (sub 2) O does not vary greatly, showing that the calibration of this ratio is feasible.