Several recent electron spin resonance studies have observed a quintet multiexciton state during the singlet fission process. Here we provide a general theoretical explanation for the generation of this state by invoking a time-varying exchange coupling between pairs of triplet excitons, and subsequently solving the relevant time-varying spin Hamiltonian for a range of transition times. We simulate experimental ESR spectra and draw qualitative conclusions about the adiabatic/diabatic transition between triplet pair spin states.
@article{arxiv.1906.08921,
title = {Fluctuating exchange interactions enable quintet multiexciton formation in singlet fission},
author = {Miles I. Collins and Dane R. McCamey and Murad J. Y. Tayebjee},
journal= {arXiv preprint arXiv:1906.08921},
year = {2020}
}