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Main Authors: Freed, Matthew, Rouse, Dominic M., Rocco, Andrea, Al-Khalili, Jim, Florescu, Marian, Burgess, Adam
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2508.11445
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author Freed, Matthew
Rouse, Dominic M.
Rocco, Andrea
Al-Khalili, Jim
Florescu, Marian
Burgess, Adam
author_facet Freed, Matthew
Rouse, Dominic M.
Rocco, Andrea
Al-Khalili, Jim
Florescu, Marian
Burgess, Adam
contents Many organic molecules possess large permanent dipole moments that differ depending on the electronic state. These permanent dipoles influence both intermolecular coupling and interactions with the optical fields, yet they are often neglected in typical theoretical quantum optics treatments. Here, we investigate the optical properties and their effect on dark states of dimers possessing such permanent dipoles. We show that when monomers have excitation-dependent permanent dipoles, optical transitions between the bright and dark states of the dimer are enabled. We investigate how permanent dipoles allow for the existence of static driving terms between the ground and excited states of each monomer. In turn, these can cause the excited states of the monomers to couple indirectly to the zero excitation state of the dimer. This leads to interference between permanent and transition dipoles and can result in the formation of dark states that are entirely localised. Furthermore, dark states formed through indirect coupling exhibit enhanced robustness against energy level fluctuations, which may improve the efficiency of the design of photovoltaic devices.
format Preprint
id arxiv_https___arxiv_org_abs_2508_11445
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Effect of Permanent Dipoles on Dark States in Molecular Dimers
Freed, Matthew
Rouse, Dominic M.
Rocco, Andrea
Al-Khalili, Jim
Florescu, Marian
Burgess, Adam
Quantum Physics
Many organic molecules possess large permanent dipole moments that differ depending on the electronic state. These permanent dipoles influence both intermolecular coupling and interactions with the optical fields, yet they are often neglected in typical theoretical quantum optics treatments. Here, we investigate the optical properties and their effect on dark states of dimers possessing such permanent dipoles. We show that when monomers have excitation-dependent permanent dipoles, optical transitions between the bright and dark states of the dimer are enabled. We investigate how permanent dipoles allow for the existence of static driving terms between the ground and excited states of each monomer. In turn, these can cause the excited states of the monomers to couple indirectly to the zero excitation state of the dimer. This leads to interference between permanent and transition dipoles and can result in the formation of dark states that are entirely localised. Furthermore, dark states formed through indirect coupling exhibit enhanced robustness against energy level fluctuations, which may improve the efficiency of the design of photovoltaic devices.
title The Effect of Permanent Dipoles on Dark States in Molecular Dimers
topic Quantum Physics
url https://arxiv.org/abs/2508.11445