Absorption spectra were studied for two series of 3 cyanine dyes with varying lengths of conjugated hydrocarbon chains. As the concentration of dyes were changed up to 10,000 fold, fine sturcture in absorption spectra were analyzed to determine its concentration dependence. In all 6 dyes studied, ratios of minor peaks to the major peak remained constant within the experimental error. These results indicate that the origin of the absorption fine structure is the electronic coupling, an intramolecular process, rather than the dimerization, an intermolecular process. Effort to identify the vibrational mode responsible for the fine structure will also be described.
Back to Undergraduate Poster Session
Back to The 37th Middle Atlantic Regional Meeting (May 22-25, 2005)