EXCITON, EXCHANGE, AND THROUGH-BOND INTERACTIONS IN MULTICHROMOPHORIC MOLECULES - AN ANALYSIS OF THE ELECTRONIC EXCITED-STATES

Electronic excitation spectra of rigidly bridged aromatic chromophores (naphthalene and perylene) are analyzed with the help of WDO/S-SCI calculations. The interactions between the chromophores, with varying mutual orientation, are interpreted in terms of exciton, exchange, and through-bond interactions. Electronic spectra of naphthalene, perylene, and tetranaphthylene are presented. Symmetries of excited states up to an energy of 65 000 cm(-1) are derived from the polarized luminescence and excitation spectra. Phosphorescence spectra of naphthalene and tetranaphthylene are interpreted as due to triplet-excimer formation. Monomer spectra are used to analyze the computed spectra of covalently linked chromophores. It has been shown that INDO/S computations give excellent results that would be helpful to interpret the electronic spectra of multichromophoric molecules.