Computer simulation studies of electron transfer parameters for cyanoanthracene/N,N-dimethylaniline solutions

Abstract

The relevant parameters for photoinduced electron transfer in solutions of 9-cyanoanthracene in N,N′ dimethylaniline solvent are investigated. Using a combined molecular-dynamics–quantum-mechanics approach we calculate the dependence of the transfer matrix element on distance and relative orientation of donor and acceptor. Different contributions to the reorganization energy from intramolecular vibrations, relative motion of donor and acceptor and the rearrangement of the solvent are investigated. We find a rather strong coupling of the optically excited state to ion pair states involving the first solvation layer. Low energy excitations are identified as exciplex states which carry large permanent dipole moments as well as considerable intensities. Coupling of the excited acceptor to solvent molecules outside the first layer is considerably weaker and can be well described by the conventional electron transfer theory.