VIBRATIONAL-SPECTRA OF LIQUID HCL

We report quantitative measurements of the infrared spectra intensities and of the Raman cross section for liquid HCl. The local field effect and the induced dipole moment account for the observed intensity enhancement. Our calculation is based on the reaction field approach. On the other hand, we show that the local field effect and the dipolar term in the intermolecular interaction energy are not sufficient to explain the frequency shift. We also show that the first overtone is mainly due to simultaneous transitions of two molecules from the ν = 0 to the ν = 1 levels and our calculations give the right order of magnitude of its intensity. Finally, we can reproduce the lineshape of the first overtone by a dissipative coupling which is derived from Redfield's theory of relaxation. © 1979.