SAMOP 2023 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 22: Theoretical and Computational Molecular Physics

MO 22.6: Vortrag

Freitag, 10. März 2023, 12:30–12:45, F142

Molecules for photodynamic therapy. Photophysical properties of 1O2 and1,3-diphenylsobenzofuran — •Stefan Stan and Vasile Chis — Babes-Bolyai University, Faculty of Physics, Cluj-Napoca, Romania

The first part of the study focuses on the calculation of the excitation energies of the O2 molecule in the first and second excited states, using the [8,6]-CASSCF method and the complete basis set extrapolation technique. The calculated energies are 0.983 and 1.671 eV, in excellent agreement with the available experimental data (0.98 and 1.63 eV). As a result of the transition to the first excited state, the DPBF molecule is significantly planarized, and the bond lengths undergo significant changes only in the benzofuran group.

Several density functionals were tested for the reproduction of the photophysical parameters of the molecule, and the results clearly show that the cam-B3LYP functional provides the best agreement with the experimental data, for all photophysical parameters.

The first excited state of the molecule is due to the π-π* transition between the HOMO-LUMO orbitals. The transition was described based on the natural transition orbitals and the difference between the electronic densities corresponding to the excited state and the fundamental one. An excellent agreement has been obtained between the experimental radiative lifetime (5.52 ns) and the calculated calculated counterpart (5.34 ns) at PCM(DMSO-cam-B3LYP/6-311G(2d,p)//APFD/6-311+G(2d,p) level of theory.