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arXiv · 2411.14282

Singlet Fission in Carotenoid Dimers -- The Role of the Exchange and Dipolar Interactions

Alexandru G. Ichert·William Barford
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Abstract

A theory of singlet fission in carotenoid dimers is presented which aims to explain the mechanism behind the creation of two uncorrelated triplets. Following the initial photoexcitation of a carotenoid chain to a "bright" $n^1B_u^+$ state, there is ultrafast internal conversion to the intrachain "dark" $1^1B_u^-$ triplet-pair state. This strongly exchanged-coupled state evolves into a pair of triplets on separate chains and spin-decoheres to form a pair of single, unentangled triplets, corresponding to complete singlet fission. The simulated EPR spectra for lycopene dimers shows a distinct spectral signal due to the residual exchange coupling between the triplet-pairs on seperate carotenoid chains.

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Alexandru G. Ichert, William Barford. 2024-11-21. Singlet Fission in Carotenoid Dimers -- The Role of the Exchange and Dipolar Interactions. https://arxiv.org/abs/2411.14282

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