The spectral width of the MD-based IR and Raman spectra is determined by the time interval ∆t between the selected snapshots, where the maximum wavenumber is νmax = 1/(2c∆t). Choosing a time step of 2.5 fs corresponds to a spectral range up to a wavenumber of 6671.28 cm -1 . The resolution of the spectra is connected to the correlation depth τ max and can be enhanced by, e.g., data mirroring as described in Section 3.2.2.