Theoretical Study On Electron Transfer Of Organic Small Molecular

In this work, we have calculated the intramolecular and intermolecular electron transfer by ab initio method. First, the relation between the intermolecular electron transfer and the stabilization energies or electron transfer matrix element is investigated. In addition, we have studied how the different substituted groups affect the intromolecular electron transfer. In the last, we have investigated the electron transfer in solvents.Charge transfer in some small group-benzene sandwich compounds was studied by density-functional method. Charge transfer was discussed at the equilibrium geometry. The relation between the maximum stabilization energies and charge transfer is analyzed. The electron transfer matrix element Vrp was calculated by the Koopmans' theorem at the DFT/B3LYP level of theory.The sequence change of charge local excited (LE) and charge transfer (CT) is investigated by substituted electron donor or acceptor at the B3LYP/6-31++G(d,p) level. By molecular orbital analysis, the sequence of LE and CT has changed with the increasing ability of electron donor or the decreasing ability of electron acceptor.In the calculation of solvent effect, we have compared the results calculated by the Polarized Continuum Model (PCM) with the ones calculated by the Self-consistent Isodensity Polarized Continuum Model (SCI-PCM) and have found the results calculated by the PCM are in more agreement with the experimental data. Then excited states of compounds in different solvents have been calculated by PCM. Compared the results in solvents with the ones in gas phase, the spectrum of CT state has a large red shift, however, the spectrum hardly changes in LE state. The solvent effect on photoinduced charge transfer between N,N-dimethylaniline and quinone has been investigated. Geometries of the isolated donor and acceptor have been optimized using B3LYP/6-31G** method. Two relative stable conformers P and T of the complex have been obtained with the symmetry of Cs. Excited states of the complex have been calculated at the level of CIS/6-31+G** in the gas phase. The results indicate that the complete charge separation within the complex occurs in the third excited singlet state of P, but only partial charge transfer for the same excited state for T. At the same basis set level, excited states of the complex in solution have been investigated. Comparing the results in solution with the gas-phase ones, the charge separation of the third excited singlet states of both conformers is very good. The absorption spectrum in solution has a large red shift.