\Delta_{TO}$                                                     energies of longitudinal and transverse optical phonon
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The absolute energies of the emission lines correspond to the energy differences between the initial state and the final states. To fit the dispersions of these emission lines, we compute the energy of the initial trion state as the sum of its single-particle energies plus the corresponding Coulomb and exchange terms. For the Coulomb energy terms, we assume a symmetric confinement as the corresponding energy terms can be easily computed analytically [@Warburton1998; @Cheng2003; @Lobl2018]. Coupling terms admixing higher shells are not considered in this estimation [@Warburton1998; @Cheng2003].

At a magnetic field of $B\simeq8\ \text{T}$, the $p_-$- and the $d_+$-shells anticross. This is not a feature of the energy spectrum of an asymmetric harmonic oscillator. The anti-crossing is included by a phenomenological coupling $\Delta_{pd}$ between $p_-$- and $d_+$-shell. We speculate that the coupling between both shells arises due to the deviation from a harmonic confinement.

When part of the energy is transferred to an LO-phonon, the corresponding photon energy is given by, $E_{\text{trion}}-E_{\text{f}}^s-\Delta_{LO}$. This emission has the same weak magnetic field dependence as the resonance fluorescence ($s$-shell emission).

The results of fitting our model are shown in Fig. \[fig:mechanismFull\] and Fig. 