The fluorescence of triplet excitons and color-centers is strongly dependent on magnetic field that mixes the zero field spin eigenstates that determine the radiative recombination rates back into the singlet ground state through spin-orbit coupling. For films of molecules, and polycrystalline color-centers samples an average over molecular orientations has to be performed to model the magneto-fluorescence lineshapes. This limits our analytical understanding of the lineshapes and complicates the analysis of the fluorescence dependence on magnetic field. Here, we present a framework that allows to average over triplet molecular orientations analytically. Our approach provides very accurate numerical routines computing precisely the averages matrix elements that appear in magneto-fluorescence and semi-analytical approximations that can be used to model experimental traces.
@article{arxiv.2512.03261,
title = {Analytical approach to the magneto-fluorescence of triplet excitons},
author = {Yan Sun and A. D. Chepelianskii},
journal= {arXiv preprint arXiv:2512.03261},
year = {2025}
}