Absorption, Photoluminescence, and Polarized Raman Spectra of a Fourfold Alkoxy-Substituted Phthalocyanine Liquid Crystal

Absorption, photoluminescence, and Raman scattering measurements have been performed on a fourfold alkoxy-substituted phthalocyanine in solution and in the discotic liquid crystal phase. As already known for this class of compounds, the features of the electronic spectra in the condensed state are determined by the spatial closeness and arrangement of the π systems of the phthalocyanine cores, with the occurrence of collectively excited states and excimer-like emission. Quantitative information about the alignment of the molecules which compose the liquid crystal phase has been obtained from the analysis of polarized Raman spectra of homeotropically aligned samples.