Charge transfer optical absorption and fluorescence emission of 4-(9-acridyl)julolidine from long-range-corrected time dependent density functional theory in polarizable continuum approach

• Combination of LC-DFT and PCM approaches is applied to CT-system (julolidine derivative).
• Absorption and fluorescence energies are calculated using parameterized LC-BLYP potential.
• Solvent dependent range separation appears to be crucial in LC-DFT/PCM computations.

A long-range-corrected time-dependent density functional theory (LC-TDDFT) in combination with polarizable continuum model (PCM) have been applied to study charge transfer (CT) optical absorption and fluorescence emission energies basing on parameterized LC-BLYP xc-potential. The molecule of 4-(9-acridyl)julolidine selected for this study represents typical CT donor–acceptor dye with strongly solvent dependent optical absorption and fluorescence emission spectra. The result of calculations are compared with experimental spectra reported in the literature to derive an optimal value of the model screening parameter ωω. The first absorption band appears to be quite well predictable within DFT/TDDFT/PCM with the screening parameter ωω to be solvent independent (ω≈0.245ω≈0.245 Bohr−1) whereas the fluorescence emission exhibits a strong dependence on the range separation with ωω-value varying on a rising solvent polarity from about 0.225 to 0.151 Bohr−1. Dipolar properties of the initial state participating in the electronic transition have crucial impact on the effective screening.

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