Structural relaxations in electronically excited poly(para-phenylene)

TL;DR

This study investigates how the structure of poly(para-phenylene) relaxes when electronically excited, using advanced computational methods to accurately predict excitonic state energies and associated structural changes.

Contribution

It demonstrates that constrained density-functional-theory can effectively model structural relaxations in excitonic states of poly(para-phenylene), providing accurate energy and structural shift predictions.

Findings

Relaxations extend over about 8 monomers.

Energy reduction of 0.22 eV due to relaxation.

Stokes shift of 0.40 eV observed.

Abstract

Structural relaxations in electronically excited poly(para-phenylene) are studied using many-body perturbation theory and density-functional-theory methods. A sophisticated description of the electron-hole interaction is required to describe the energies of the excitonic states, but we show that the structural relaxations associated with exciton formation can be obtained quite accurately within a constrained density-functional-theory approach. We find that the structural relaxations in the low-energy excitonic states extend over about 8 monomers, leading to an energy reduction of 0.22 eV and a Stokes shift of 0.40 eV.