The (shifted) B-band is located approximately 0.12 eV (994 cm -1 ) to the red of the corresponding peak in experiment, indicating that the computed energy gap between the first and second peak is too small. This is again within the error of CC2. If we align the spectra according to the B-band instead of the Q-band, the overall red shift is reduced to 0.23 eV (1825 cm -1 ). However, this worsens the alignment of the high-energy region. Spectra shifted to align with the B-band are available in Figures and in the SI.