Theoretical Investigation On Photoinduced Electron Transfer And Solvent Effect

Photoinduced eletron transfer (ET) is one of the most pivotal processes in photosynthesis, orgnic reactions and optelectronic devices. In this work, theoretical calculations for the photoinduced intermolecular electron transfer and solvent effect of chloranil-biphenylene(CL-BP) complex by means of ab initio method have been performed. The interaction energy between electron donor and acceptor was investigated using second order M0ller-Pleasset method, and the couterpoise method was adopted to consider the correction of basis set superposition error (BSSE) for the interaction energy. Presuming that the inner structure keeps unchanged in the formation of the encounter complexes, the stable conformation of the complex has been determined by means of optimizing the center-center distance between the donor and the acceptor. Through the construction of the potential energy curve, the energy minimum has been found. Four low-lying excited singlet states of CL-BP complex have been investigated by using the method of configuration interaction singles(CIS). It is concluded that CL and BP can form a stable electron donor-acceptor complex and light absorption can directly produce excited charge transfer state(CT). Based on the approximation of spherical cavity and point dipole, the solvation correction of the absorption spectrum has been made for the charge transfer transition. The result shows that the theoretical calculation agrees well with the experimental observations.Excited state intramolecular proton transfer (ESIPT) and dual fluorescence properties of 3-hydroxyflavone (3HF) have been investigated using time-dependent density functional theory. Our investigation shows that the green fluorescence band can be assigned to the tautomer state generated by the ESIPT process whereas the blue-violet fluorescence can be assigned to the S1 S0 fluorescence of the normal state 3HF molecules.