Fig. 6

Temperature evolution of integrated intensity Raman bands assigned to Re–O and Si–O vibrations in spectra of fluids as indicated on each curve. Pressures corresponding to each temperature can be read off Fig. 2. Raman intensities are normalized to the same Raman setup parameters (acquisition time and slit width). A Intensity evolution with temperature (and pressure) of bands assigned to Re–O vibrations in fluid from the ReO₂–SiO₂–H₂O. B Intensity evolution with temperature (and pressure) of bands assigned to Re–O vibrations in fluid from the Na₂O–ReO₂–SiO₂–H₂O. C Temperature evolution of intensity of Si–O stretch vibrations from isolated SiO₄ tetrahedra (780 cm⁻¹ band) in fluids in systems that contain SiO₂. D Temperature evolution of intensity of Si–O–Si bend vibrations from polymerized SiO₄ tetrahedra (650 cm⁻¹ band) in fluids in systems that contain SiO₂