Vibrational spectra of polar fluids

Considerable changes of B and are also observed (Fig. 6.7-10) in the vibrational fundamental of pure hydrogen chloride, measured at various densities g and at 100 °C, which is above the critical temperature T,. = 51 °C). At the lowest density, the familiar spectrum with P and R- branches is obtained. The rotational structure is lost with increasing density, and at the highest density there is a single, nearly symmetrical band. 

The position of the O-D band maximum has also been used to indicate the structure of fluid electrolyte solutions. Fig. 6.7-12 shows the wavenumber of the O-D band maximum, Vmax, in aqueous (HDO/H2O) lithium chloride solutions at 2800 bar and various temperatures as a function of the LiCl content x (in mol %) (Valyashko et al., 1980). The 25 °C isotherm is measured at 20 bar. If x is small, i ax is considerably dependent 

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