Electron-Lattice Dynamics in pi-Conjugated Systems

This dissertation examines notably the dynamics of a unique type of quasi-particle in pi-conjugated materials termed polaron, the origin of which is totally associated with the strong interactions between the electronic and the vibrational degrees of freedom in these systems. To be able to perform these studies with the particular focus of each appended paper, we concurrently solve the time-dependent Schrödinger equation and the lattice equation of motion with a three-dimensional extension of the famous Su-Schrieffer-Heeger (SSH) model Hamiltonian. Especially, we illustrate in Paper I the applicability of the approach to model transport dynamics in molecular crystals in a region were neither band theory nor perturbative treatments like the Holstein model and extended Marcus theory apply. In Paper 2 we broaden the model Hamiltonian to deal with the revolution of phenylene rings around the sigma-bonds and show the great affect of stochastic ring torsion on the intra-chain mobility in conjugated polymers using poly[phenylene vinylene] (PPV) as a model system. Lastly, in Paper 3 we go over the initial reason for the methodology and use its excellent flexibility to examine radiationless relaxations of hot excitons…

Contents: Electron-Lattice Dynamics in pi-Conjugated Systems

1 Introduction
1.1 Adiabaticity
1.2 Outline of Research
1.3 Outline of Thesis
2 Storage and Transport of Charge
2.1 Electronic Structure of Conjugated Polymers
2.2 Charge Storage in Conjugated Polymers
2.3 (Non-)Adiabatic Polarons
2.4 (Non-)Adiabatic Polaron Transport
3 Model and Method
3.1 General Considerations
3.2 Model Hamiltonian
3.3 Statics
3.4 Dynamics
4 Comments on Papers
4.1 Paper I
4.2 Paper II
4.3 Paper III (in manuscript form)…

Source: Linköping University

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