Optical spectra and structure of oligomeric models of polyparaphenylenevinylene

Abstract

This paper treats the vibrational and UV/visible spectra of oligomers of polyparaphe- nylenevinylene (PPV) and lays the background knowledge for the treatment of the spectra and structure of PPV which is treated in the paper that immediately follows. The problem of the molecular conformation of these systems is faced both with MNDO (modified neglect or differential overlap) calculations and with infrared-Raman experiments. Oligomers are certainly twisted in noncrystalline phases while may approach coplanarity in the solid. Fourier transform Raman spectra are recorded and are interpreted in terms of the recently developed theory of the effective conjugation coordinate.