Organic Materials for Multiphoton Absorption: Time-Dependent Density Functional Theory Calculations

In our interest to accurately predict the photophysical properties of organic molecules that exhibit multiphoton absorption optical processes, we applied density functional theory (DFT)/time-dependent DFT (TDDFT) for the calculation of structures, and one- photon absorption (OPA), two-photon absorption (TPA) spectra, for series of relevant compounds. In our recent work TDDFT was validated regarding the exchange- correlation functional to be used for molecules that exhibit excited state charge-transfer characteristics, the application of quadratic response for TPA properties, and the inclusion of solvent effects, as applied, for example, to 4,4´-dimethyl-amino-nitrostilbene and a donor-acceptor (DA) fluorene-based system. In this work we discuss the prediction of TPA cross-section enhancements for large porphyrin dimers.