Ultraviolet (UV) Raman spectroscopy study of the Soret effect in high-pressure CO2-water solutions.

Spatially resolved deep-ultraviolet (UV) Raman spectroscopy was applied to solutions of CO(2) and H(2)O or D(2)O subject to a temperature gradient in a thermally regulated high-pressure concentric-tube Raman cell in an attempt to measure a Soret effect in the vicinity of the critical point of CO(2). Although Raman spectra of solutions of CO(2) dissolved in D(2)O, at 10 MPa and temperatures near the critical point of CO(2), had adequate signal-to-noise and spatial resolution to observe a Soret effect with a Soret coefficient with magnitude |S(T)| > 0.03, no evidence for an effect of this size was obtained for applied temperature gradients up to 19 °C.