Fig. 4

Infrared absorption spectra of fluids in the spectral region of C–O stretching in CO2 molecules as a function of temperature and pressure (see Table 1 for pressures). The spectra are offset for clarity. The vertical line is the scale bar for the Absorption intensity of the spectra. Inserts A and B show the integrated intensities of the absorption and an example of 2-line curve-fitted infrared spectrum by using Gaussian line shape. The spectrum shown was recorded while the sample was at 750 °C. Dashed line is from 800 °C where a single fluid phase only exists