Fig. 8

Examples of Raman spectra in the high-frequency range (3000–4000 cm⁻¹) of fluids in all systems investigated at temperatures indicated on diagrams. Corresponding pressures can be read from Fig. 2. Spectra are normalized to the same acquisition time and slit width and then normalized to the maximum intensity within each spectrum. A, C, F H, K, and N. 3600 cm⁻¹ envelope at temperature conditions indicated on each spectrum. Intensities are normalized to the highest intensity point in each spectrum. B, D, G, I, L and O. Difference spectra relative to the spectrum at the highest temperatures as indicated on each graph by temperature of each of the two spectra. Corresponding pressures can be read from Fig. 2. E, J, M and P. Full width at half height (FWHH) of the 3600 cm⁻¹ envelopes from fluids in all systems as indicated on individual lines, as a function of temperature. Corresponding pressures can be read from Fig. 2. Q Comparison of temperature-dependence of FWHH from the high-frequency, ∂FWHH/∂T, spectra of all the fluids as indicated in the diagram