Experimental setup to measure the Raman signal of dissolved CO₂ as a function of pressure. (1) 1000-mL stainless-steel cylinder. The upper end of the cylinder is connected to a pump (2), a pressure transducer (3), and a bottle of pure compressed CO₂ (4). The Raman probe (6) is introduced via the other end of the cylinder which is then closed by a special tor to ensure there is no water leakage. The Raman probe is connected to a Raman RXN2 spectrometer (7) by a 100-m optical fiber.