EXPERIMENTAL AND THEORETICAL-STUDIES OF ABSORPTION AND PHOTOLUMINESCENCE EXCITATION-SPECTRA OF POLY(P-PHENYLENE VINYLENE)

In this paper, we present the experimental absorption spectra and phot oluminescence excitation spectra of poly(p-phenylene vinylene) (PPV). We also present the theoretically calculated absorption and photolumin escence spectra of PPV. The singlet-to-singlet transition energies and moments calculated from the intermediate neglect of differential over lap with the spectroscopic parametrization (INDO/S) semi-empirical met hod were used to analyze the absorption spectra. The symmetrical vibra tional modes calculated from the abinitio method were used to obtain t he vibronic features in the spectra of PPV. It is demonstrated that th e inhomogeneity observed in the absorption spectra of PPV can be model ed by summing up the absorption of PPV oligomers with different chain lengths. The difference between absorption and photoluminescence excit ation spectra is explained.