Fig. 2. Sum of the electronic coherences over the entire 2D spectrum. (a) The BChla spectra contains only vibrational coherences. With the long-lived coherences subtracted, no additional peaks are observed. Both (b) FMO and (c) LH2 have multiple electronic states within the bandwidth of the pulse and display fast decaying coherences. For FMO, excitonic energy level differences are drawn as a stick spectrum for differences between 330–550 cm^–1. The closest excitonic energy level difference to the main peak is between excitons 7 and 2 at 400 cm^–1, with the energy levels taken from ref. 22.