Theoretical study on nonlinear and quantum optical phenomena of dendritic systems interacting with quantum laser field

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Various physical and chemical phenomena for the interaction between supramolecular systems including dendritic systems and laser fields have been investigated theoretically and computationaly. The achievements are described as follows.1.We have developed a general calculation method treating multi-state model interacting with various quantum fields and investigated the effects of multi-photon process, which is one of nonlinear optical effects, on such dynamics. In particular, we have developed a novel method treating relaxation effects caused by molecular vibration and collision on the dynamics using a quantum master equation approach. For a dimer model system interacting with a two-mode quantum field, the collapse-revival phenomena of excited state population for dimer systems are found to be remarkably affected in oscillation amplitude and revival time by the intermolecular dipole-dipole interaction. The pure-phase and population relaxations of dimer systems are turned out to destroy … More the coherency between dimer electronic states, leading to the significant attenuation of molecular nonlinear optical effects. Several additional effects, i.e., exciton relaxation rates and quantum statistics of external quantum fields, on the dynamics and nonlinear optical phenomena of dendritic systems are now being investigated.2.We have studied light harvesting and dynamic nonlinear optical phenomena of supramolecular systems including dendritic systems in order to elucidate the structure-property relationship. A novel calculation method of dynamic nonlinear optical properties of one-exciton molecular aggregate model systems have been developed and applied to the calculation of nonlinear optical spectra of nanostar dendritic aggregate systems with various exciton migration rates. The pure-dephasing caused by the exciton migration originating in the exciton-phonon coupling has been turned out to significantly increase the spectrum width and decrease the peak. In order to treat real supermolecular systems, e.g., dendrimers, we have developed a quantum master equation method based on the ab initio molecular orbital configuration interaction (CI) and have clarified that the efficient directed energy migration originates in the partial penetration of πconjugation through meta-substituted benzene ring. We have also started to examine the open-shell molecules as a unit (building block) of supramolecular systems, and have theoretically found that the nonlinear optical effects significantly depend on the spin state and diradical character. This attractive result is expected to be a novel class of systems in the field of nonlinear optical materials. Less