Impact of ring torsion dynamics on intrachain charge transport in conjugated polymers

Based on an approach including both the time-dependent Schr\"odinger equation and an effective Newton's equation for the ionic motion, we study the impact of ring torsion dynamics on the intrachain charge transport process in conjugated polymers. As model systems we have used single chains of poly(para-phenylene-vinylene). Without any external electric field, the dynamics of the phenyl ring torsion is the dominant property controlling intrachain charge propagation. The charge is coupled to both ring torsions and bond lengths distortions, which results in a significantly more localized polaron state than in a planar chain. In the presence of an electric field, the charge can breach the barriers caused by ring torsions, a process that involves nonadiabatic effects and a temporary delocalization of the polaron state.