High Pressure Light Scattering Studies of Dense Fluids (Collision, Induced, Lineshape)

130 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.High pressure light scattering experiments are a powerful tool for probing the density dependence of both molecular motion and intermolecular interactions. This thesis describes high pressure light scattering studies of the vibrational relaxation of the nitrate ion in aqueous solutions of sodium nitrate and of collision induced light scattering in methane, sulfur hexafluoride and carbon dioxide.The effect of hydrogen bonding on vibrational relaxation is investigated by studying the effects of changes in concentration, pressure and temperature on the (nu)(,1) Raman lineshape of the nitrate ion in aqueous solutions of sodium nitrate. The lineshape is found to be inhomogeneously broadened and asymmetric at higher concentrations of sodium nitrate.Experimental results are presented on both the density and temperature dependence of the collision induced depolarized Rayleigh spectra (DRS) of both methane and sulfur hexafluoride. As the DRS of both fluids are found to be roughly exponential, the spectra are characterized by an exponential decay constant (DELTA). Experimental values for (DELTA) are then compared to the predictions of several theoretical models. The DRS of sulfur hexafluoride is calculated using relevant lineshape theories. The results from this calculation are then compared to the experimentally obtained lineshapes.The density dependence of the DRS of carbon dioxide is investigated. Emphasis is placed on the study of collision induced scattering in the wings of the DRS. The results are then compared to those of similar experiments on the linear triatomics carbon disulfide and carbonyl sulfide.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD