Calculation of infrared and raman spectra for PPV

Summary form only given. Using a modified Su-Schrieffer-Heeger-like model that explicitly includes in-plane geometry of the poly(p-phenylene vinylene) polymer we have calculated self-consistent electronic and vibrational spectra in the ground state as well in the presence of polaronic defects. We computed the parameter sets from the experimental ground state data. The phonon, infrared (IR), nonresonance and resonance Raman (RR) spectra were calculated using the random field approximation (RPA) in which the quantum fluctuations are explicitly incorporated around the mean field solution (lattice distortion). The IR spectrum was obtained from the two-body correlation function for polarizability while the RR spectrum was calculated from the cross-sections associated with the absorption and emission transition rates between phonon levels. The localized modes that strongly couple to the intragap, electronic states are identified in the IR as well as in the RR spectra. The predicted IR and RR are compared with available experimental data.