The use of low temperature infra red spectroscopy in the study of ionic solvation.

This thesis is concerned with the theoretical and esqjerimental aspects of low temperature infra red spectroscopic studies of ionic solvation. Isotopically dilute methanolic and aqueous solutions were investigated in the fundamental infra red region, particularly in the 0-H stretching region of the spectrum. Systematic room temperature investigations were undertaken for aqueous and methanolic electrolyte solutions as a fimction of the salt concentrations. These results provided certain trends regarding solvent- solute interactions which the low temperature experiments on the same solutions confirmed so that cation and anion solvation models could be put forward. ParticiiLar attention was given to the study of methanolic and aqueous polyatomic ion solutions to provide further evidence as to whether these anions cause the formation of free or weakly bonded 0-H groups. Infra red studies of the tetrahydroborate anion in various pure solvents and binary mixtures suggested an interaction between BH.;and water protons which had spectroscopic characteristics of hydrogenbonding. Finally vibrational studies of methanolic tetraalkylammonium halide solutions in inert and bulk solvent solutions produced a range of anion solvates where both primary and secondary solvation could be observed.