Fig. 2

FTIR spectra of fluid at temperatures indicated. Corresponding pressures can be found in Table 1. The dashed line is the spectrum from a single-phase fluid. Insert shows expanded view of frequency region centered at 4500 cm−1. Note that all spectra are offset for clarity. The 0-intensity line passes through the background at 600 cm−1. In the insert, the 0 line is approximately that near 4300 cm−1