Snapshots of solvated CV + generated from both the FFMD and QM/MM AIMD simulations were used for the calculation of QM/MM excitation energies with TDDFT using CAM-B3LYP/ 6-31G(d) within the Tamm-Dancoff approximation (TDA). The MM point charges of the solvent were electrostatically embedded in the QM Hamiltonian. The TeraChem GPU accelerated electronic structure package was used for all vertical excitation energy calculations. The resulting excitation energies were then used to build the energy gap correlation function, employed in Eq. 4, for simulation of the spectral density and linear absorption spectra. No mixing between the bright S 1 and dark S 2 state was observed along the trajectory, see Figure . All linear spectra and spectral densities were calculated using the MolSpeckPy spectroscopy package. To obtain a wellbehaved Fourier transform, the classical time correlation function was multiplied by an exponential damping function with a decay time constant of 500 fs.