Excess polarizabilities upon the first dipole-allowed excitation of some conjugated oligomers

This paper presents theoretical predictions for the excess polarizabilities upon excitation from the ground state to the first dipole-allowed excited state (1(1)B(u)) of some conjugated oligomers. The excess polarizability was obtained by simulating the Stark shift, which was predicted by the time-dependent density functional theory (TDDFT) with the hybrid Becke-3 Lee-Yang-Parr (B3LYP) potential. The Stark shift in solution was simulated by employing the non-equilibrium integral equation formalism polarizable continuum model (IEFPCM). All the model molecules considered in this study were fully optimized by the Hartree-Fock (NF) method and the density functional theory (DFT) with the B3LYP potential, respectively. For diphenylpolyenes, the excess polarizabilities displayed by the DFT/B3LYP-optimized geometries are more reasonable than those displayed by the HF-optimized geometries when compared with the experimental results. However, this feature is not clearly demonstrated by our results in the cases of oligo(phenylenevinylene)s (OPVs). Copyright (C) 2008 John Wiley & Sons, Ltd.