Once the trajectory is equilibrated, the ion is located between two nitrogen atoms in a stable configuration that lasts for the full 36 ps of computed QM/MM trajectory (Fig. ), with an average distance to the two nearest nitrogens of 5.2 Å and 5.3 Å respectively. The close association with the N atoms throughout the entire trajectory suggests that the chloride ion forms a stable contact ion pair with CV. Interestingly, while the optimized geometry for CV in vacuum has the counterion mainly associated with a single N , in toluene the ion is found to have a higher tendency to be equidistant to both N (see Fig. ). The equidistant positioning of the ion leads to less symmetry breaking of the CV electronic structure compared to the optimized vacuum position, leading to an overall smaller energy splitting between the S 1 and S 2 excitations compared to the vacuum configuration. An example of an equidistant is shown in Fig. . The greater the difference in distance to the two nearest nitrogens, the greater the symmetry breaking of the CV molecule, resulting in a larger S 1 -S 2 energy difference (see Fig. , as well as Fig. ). Along the 36 ps trajectory of CV in toluene, the average difference in distance to the two N atoms is 0.75 Å and the average S 1 -S 2 energy difference is 0.51 eV, resulting in a wide splitting of 0.475 eV between the peaks in the simulated absorption spectrum (Fig. ), that is nevertheless smaller than the splitting for CV in the presence of a counterion in vacuum (see Table and Fig. ). To further analyze the origin of the large S 1 -S 2 splitting in nonpolar solvents, we performed vertical excitation energy calculations along the same MD trajectory snapshots in toluene, but with the counterion omitted from the calculation. The resulting spectrum is shown in the right panel of Fig. , confirming that the main contribution to the symmetry breaking and strong S 1 -S 2 splitting in the absorption lineshape is due to the electrostatic interaction between CV and the chloride ion. When removing the ion, the absorption lineshape exhibits a strongly reduced splitting of 0.108 eV, which is significantly smaller than the experimentally observed splitting.