Lattice dynamics and vibrational spectra of polythiophene. I. Oligomers and polymer

Abstract

The vibrational dynamics of oligomers of thiophene is treated theoretically and the experimental infrared and Raman spectra are studied with the main purpose to derive information for the interpretation of the spectra of polythiophene. The optimized geometries and the vibrational force field are calculated for the oligomers Thn (n=1, 2, 3, 4, and 6) and the parameters are used for PTh. For PTh and two isotopic derivatives dispersion curves and k=0 phonons frequencies are calculated and a vibrational assignment is proposed.