Theory of non-Condon emission from the interchain exciton in conjugated polymer aggregates
Related Experiment Video
Updated: Jul 14, 2026

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering
Published on: December 21, 2017
Eric R Bittner1, Stoyan Karabunarliev, Laura M Herz
1Texas Center for Superconductivity, Department of Chemistry, University of Houston, Houston, Texas 77204, USA. bittner@uh.edu
Abstract:
The authors present here a simple analysis that explains the apparent strengthening of electron phonon interaction upon aggregation in conjugated polymer materials. The overall scheme is that of an intermolecular Herzberg-Teller effect whereby sidebands of a forbidden transition are activated by oppositely phased vibrations. The authors show that upon aggregation, the 0-0 emission becomes symmetry forbidden and the apparent redshift and remaining vibronic structure are due to sideband (0-1,0-2, etc.) emission. At higher temperatures, the 0-0 peak is due to thermal population in a higher lying even-parity vibronic state rather than direct emission from the odd-paritied lowest intermolecular vibronic state.
Related Concept Videos
Cationic Chain-Growth Polymerization: Mechanism
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Thermal and Photochemical Electrocyclic Reactions: Overview
Anionic Chain-Growth Polymerization: Mechanism
MO Theory and Covalent Bonding
¹H NMR: Long-Range Coupling
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene π orbitals.

