Electron-lattice relaxation, and soliton structures and their interactions in polyenes

TL;DR

This paper uses advanced computational methods to study electron-lattice interactions and soliton structures in polyenes, revealing the nature of excited states and their relaxation energies, with implications for understanding conjugated polymer properties.

Contribution

It presents detailed DMRG calculations of long polyenes incorporating Coulomb interactions and lattice relaxation, identifying soliton structures in various excited states.

Findings

2-soliton and 4-soliton structures in triplet and 2Ag states

Relaxed energy of 2Ag state is below 1Bu state

Soliton/anti-soliton pairs are bound

Abstract

Density matrix renormalisation group calculations of a suitably parametrised model of long polyenes (polyacetylene oligomers), which incorporates both long range Coulomb interactions and adiabatic lattice relaxation, are presented. The triplet and 2Ag states are found to have a 2-soliton and 4-soliton form, respectively, both with large relaxation energies. The 1Bu state forms an exciton-polaron and has a very small relaxation energy. The relaxed energy of the 2Ag state lies below that of the 1Bu state. The soliton/anti-soliton pairs are bound.